japanese ww2 medical experiments

Please enter at least 3 characters

Japan’s Hellish Unit 731

In conquered Manchuria, ghastly experiments were fiendishly conducted on human guinea pigs.

This article appears in: Fall 2018

By David D. Barrett

The final months of World War II saw the liberation of hundreds of ghastly concentration camps and the awful reality of Nazi racism. For more than seven decades those atrocities, including the use of human beings for medical experiments, have been common knowledge. Far less known is the wholesale slaughter of hundreds of thousands of Chinese by a Japanese organization known as Unit 731.

Established for the purpose of developing biological and chemical weapons, Unit 731 exceeded by a year the duration of the Third Reich. While biological and chemical weapons were not new to warfare, Japanese testing on human subjects was unparalleled even by the Nazis.

What makes this descent into barbarity all the more stunning was the Japanese contribution to medical science just three decades earlier. A U.S. Army doctor named Lewis Livingston Seaman observed colleagues who were attending to the Imperial Japanese Army (IJA) during the Russo-Japanese War (1904-1905).

Dr. Seaman came away from his experience profoundly impressed with his medical brethren, stating, “The history of warfare for centuries has proven that in prolonged campaigns the first, or actual enemy, kills 20 percent of the total mortality in the conflict, whilst the second, or silent enemy (disease), kills 80 percent.

“I unhesitatingly assert that the greatest conquest of Japan has been in the humanities of war, in the stopping of the needless sacrifice of life through preventable disease. Japan is the first country in the world to recognize that the greatest enemy in war is not the opposing army, but a foe more treacherous and dangerous—preventable disease, as found lurking in every camp—whose fatalities in every great war of history have numbered from four to twenty times as many as those of mines, bullets, and shells.

“It is against this enemy that Japan, with triumphant exaltation, may cry Banzai. For it is against this enemy that she has attained her most signal victories….”

Twenty years later, Japan signed the Geneva Convention, which prohibited biological and chemical warfare. But where other men reasoned with justification that these kinds of weapons should be banned by civilized nations, another man, a specialist in bacteria and related fields, Dr. (Colonel) Shiro Ishii, saw the prohibition as an opportunity.

He reasoned that if something were bad enough to be outlawed, then it must certainly be effective, and he began a sustained effort to establish a military arm within the Japanese Army whose aim would be the development of weapons based on biology. Ishii was highly intelligent but arrogant, merciless, and immoral.

He thought of himself beyond reproach and as a visionary. He was driven to break new scientific ground and to help Japan defeat its foes. In his quest to contribute to that effort, Ishii in time exhorted his team of physicians to violate the physicians’ ethical code: “A doctor’s God-given mission is to challenge all varieties of disease-causing micro-organisms; to block all roads of intrusion into the human body; to annihilate all foreign matter resident in our bodies; and to devise the most expeditious treatment possible….

“However, the research we are now about to embark is the complete opposite of these principles, and may cause us some anguish as doctors. We pursue this research for the double medical thrill; as a scientist … probing to discover the truth in natural science; and as a military person, to build a powerful military weapon against the enemy.”

To convince the senior levels of the Imperial Army to back his efforts, Ishii built his case around financial considerations, completely skirting either Japan’s obligation to the world community as a signatory of the aforementioned 1925 Geneva Convention or the morality of using such weapons. Ishii argued that compared with the costs of building, manning, and maintaining huge conventional forces, bacteria and gas were a far less expensive alternative.

By 1930, nationalism burned hotter than ever in Japan and created a climate receptive to Ishii’s ideas of developing biological weapons. In September 1931, Japanese forces instigated the “Mukden Incident.” The pitched battle between Japanese and Chinese forces was actually no more than a Japanese ruse used to justify a complete takeover of Manchuria.

Moreover, the area became the perfect place to develop and test Ishii’s new biological and chemical weapons, a place where he would be free to conduct any kind of experiment he deemed beneficial.

The following year, under the cover of the euphemistically named Epidemic Prevention Research Laboratory, Ishii set up shop in the Army’s hospital in Tokyo. The location was only temporary because, to accomplish his objectives, he would need access to far greater resources; Japanese ascendancy in Manchuria provided its medical community unprecedented opportunities for research (much as the Germans used concentration camps and their prisoners for their own medical and pseudo-scientific research).

Ishii’s goal of turning bacteria and gas into weapons for the Imperial Japanese Army required comprehensive study, and he believed animals could not supply usable data. Japan’s control over Manchuria delivered research materials in the form of people who were plucked from the streets and locked into black vans known as voronki (ravens), to be carried off to the waiting prison cells of Unit 731.

Japan’s Kempeitai, the military police arm of the IJA from 1881 to 1945, was tasked with these kidnappings. The Kempeitai was less a conventional military police body than a secret police force akin to the Gestapo. Headed in Manchuria by Hideki Tojo, from 1935 to 1937, the Kempeitai’s cruelty was notorious in occupied territories. (See WWII Quarterly, Fall 2011). After the war, the U.S. Army estimated it numbered 36,000 regular members.

Anxious to take operations to the next level, in 1932 Dr. Ishii chose the city of Harbin, capital of Heilongjiang Province in southwest Manchuria, as the site of Unit 731’s first biological and chemical weapons facility. The original buildout covered a 500-square-meter area and was designated a restricted military zone. A tract of land to the south of the sector was appropriated and made into an airport. It and a nearby rail line were also used to move victims to Unit 731 and transport results and specimens back to Japan’s medical community.

Japan’s medical institutions enabled the work of Unit 731 by supplying Dr. Ishii with top Japanese scientists and physicians who would be labeled Hikokumin (traitors) if they refused to take part. Most medical professionals saw their work as noble service to the Emperor; the fact that they were killing non-Japanese meant nothing to them.

Unit 731 received state-of-the-art equipment and a nearly unlimited supply of funds from the Japanese government. Even for reluctant researchers Ishii’s factories were luxurious. The annual budget for Unit 731 was ten million yen (about nine billion yen in the modern currency, or about $86 million). Salaries were very generous, and the food was exceptional.

Precipitated by an escape attempt by 40 prisoners, all of whom were captured and killed, the Harbin operation was closed and moved to the Harbin suburb of Ping Fang in 1936. This complex was a sprawling walled city of more than 70 buildings that dwarfed its predecessor in Harbin. The perimeter at Ping Fang incorporated more than six square kilometers and rivaled Auschwitz-Birkenau in size. Tucked away inside the administration building was a prison that housed 500 men, women, and children selected for vivisection.

As immense as Ping Fang was, Unit 731 also had affiliated locations in Nanking (Unit 1644), Beijing (Unit 1855), and Changchun (Unit 100). Altogether there were 26 known killing laboratories, experimental detachments, and battalions of the Army spread across occupied lands in Asia. The total number of personnel involved reached some 20,000. All units and facilities were coordinated by the Epidemic Prevention Research Laboratory under the control of Colonel Ishii.

The research was made available not just to the Army hospital in Manchuria, but to doctors and educators throughout Japan. In this way, Unit 731 was performing the service of human experimentation for the entire Japanese medical community, in an on-going feedback loop. “Medicine itself must become a weapon,” said Nakagawa Yonezo, Professor Emeritus at Osaka University.

The gruesome professionalism of Unit 731 included a touch of sardonic humor. The construction of the Ping Fang installation prompted locals to ask what it was. The answer was a “lumber mill.” Regarding this reply, one of the researchers joked privately, “and the people are the logs.”

From then on, the Japanese term for log, Maruta, was used to speak of the prisoners whose last days were spent being infected with lethal pathogens, torn apart, frozen, or gassed by Japanese researchers. The expression indicates a degree of racism far beyond disdain; it is evidence of a belief that torturing the Chinese was of no more consequence than squashing a bug.

As noted earlier, the primary objective of Ishii and Unit 731 was the creation of biological and chemical weapons. To facilitate that end, wholesale human experimentation was utilized, including the vivisection of thousands of people. The justification for performing all these surgeries came from the expectation that human tests would create better weapons.

Doctors in Unit 731 examined the first stages of disease on organs. A former member of Unit 731 described the process: “As soon as symptoms were observed, the prisoners were taken from their cells and into the dissection room, he was stripped and placed on a table, screaming, trying to fight back. He was strapped down, still screaming frightfully. One of the doctors stuffed a towel into his mouth, then with one quick slice of the scalpel he was opened up.” Witnesses reported that, without anesthesia, the victims let out horrible screams when the first cut was made and that the cries stopped soon thereafter.

A doctor at Ping Fang testified to a time when he was working on a pregnant female victim who awoke from anesthesia while being vivisected. The woman said, “It’s all right to kill me, but please spare my child’s life.” It is likely that more than one mother voiced, as a last wish on the vivisection table, the wish to let her child live. None ever did. The researchers wanted their data.

As ghastly as these procedures were, vivisections were not limited to weapons development, but fell into four categories: (1) intentional infection of diseases, (2) training newly employed army surgeons, (3) trials of nonstandardized treatments, and (4) discovering the limits of human tolerance to pain and stress.

Under the auspices of weapons development and intentional infection of diseases, prisoners were injected with various biological agents including plague, typhus, cholera, anthrax, and syphilis.

To test the effectiveness of dispersion methods for military purposes, victims were staked to crosses with their vital organs and heads protected. Various types of bombs and agents were then dropped or sprayed from specially modified planes to test the survivability of the agents and their ability to infect the subjects. Community water and food sources were also contaminated. To determine the results, mobile vivisection units were set up in the field near the infected communities.

The Imperial Japanese Army also allowed its physicians to perform vivisections on living subjects to train them in the treatment of battle wounds—procedures that are too gruesome to describe in detail.

Tests that could have real medical value were also conducted, such as finding the best method to deal with frostbite. But even here Japanese doctors chose to perform the experiments in the most merciless ways possible.

Conventional weapons tests were also carried out. Victims were tied to stakes and used to determine the operational range of flamethrowers, grenades, and various kinds of shells and bombs.

But this was hardly the extent of the tests to which the prisoners were subjected. Sheldon Harris, author of Factories of Death, stated, “They just killed people with no inherent purpose other than to see how they reacted to being killed.” People were locked into high-pressure chambers until their eyes popped out, or they were put into centrifuges and spun to death.

Other experiments involved hanging prisoners upside down to discover how long it took for them to choke to death or injecting air into their arteries to test for the onset of embolisms. Another test consisted of taking blood samples, at least 500 cm³ (slightly more than a pint) at two- to three-day intervals. Some victims became debilitated; still, the blood drainage continued.

When the human guinea pigs could no longer serve as lab material, they were abused in various manners: injected with poison, killed for their vital organs (brains, lungs, or liver), subjected to violent surgeries (e.g., amputation and reattachment of the limbs to the opposite sides of the body, resection of the stomach to attach the esophagus to the intestines). Electrical shocks were administered until the person slowly roasted to death.

Some experiments had no medical purpose whatsoever except the administering of indescribable pain, such as injecting horse urine into prisoners’ kidneys. The doctors of Unit 731, like the Nazi doctors at Dachau and Buchenwald, indulged any perversion they could imagine.

In 1938 and 1939, the Soviet and Japanese Armies clashed in two encounters near the border of Mongolia and Manchuria. The 1939 summer battle, known as the Nomonhan Incident and the Battle of Kalhin Gol by the Soviets, resulted in the overwhelming defeat of the Japanese Kwantung Army by Stalin’s Red Army.

The clash saw the first field operation of Japan’s biological warfare unit; it occurred in a desert region where water was scarce. To disable their Russian foes, the Japanese dumped large quantities of intestinal typhoid bacteria into the river.

Fortunately for the Russians, this type of typhoid germ became ineffective almost immediately after hitting the water. The contamination was probably initiated more for the publicity than anything else, as Ishii likely knew it would not work.

In 1940, Japanese planes dropped wheat, corn, rags, and cotton infested with bubonic plague on the unarmed village of Ningbo, China. More than 100 people died within a few days of the attack.

Two years later, the Japanese conducted a second attack in the same area. Japanese researchers took over a house on top of a hill about a kilometer away from the infected zone to use as a vivisection laboratory. As a result of the attacks, the Ningbo region remained sealed off until the 1960s.

During the siege of Bataan in the Philippines in March 1942, the Japanese planned to release 200 pounds of plague-carrying fleas—about 150 million insects—in each of 10 separate attacks. However, by the time the assault was ready the battle had already ended.

In June-July 1944, during the Battle of Saipan, plague-infested fleas were again to be used against U.S. forces. Fortuitously for the Americans, by this stage in the war it had become almost impossible for the Japanese to get any reinforcements and or matériel to its island bastions, and the Japanese submarine carrying the fleas was sunk en route.

For the Battle of Iwo Jima, February-March 1945, another biological attack was to be carried out against the invading Americans. Two gliders loaded with pathogens were to be towed over the battlefield and released. The gliders never reached their destination.

One of the least known Japanese efforts to attack Canada and the continental United States occurred in late 1944 and the spring of 1945. Records uncovered in Japan after the war indicated that about 9,000 balloon bombs, known as fugo, and carrying incendiary bombs, were launched into the jet stream during this period. More than 200 ultimately reached the United States. Six people were killed in Oregon when a bomb detonated on discovery. Before Japan surrendered, Ishii and Army leaders proposed using balloon bombs filled with cattle plague and anthrax.

As part of Japan’s defense of Okinawa in the spring of 1945, Unit 731 had developed plans to meet the American invaders with plague bacteria. The attacks were never carried out because once again fleas carrying the plague could not be delivered to the island. The native Okinawan population only learned of this plan in 1994.

Operation PX, aka Cherry Blossoms at Night, were the codenames for the Japanese plan for a biological attack on cities in southern California. The plan was completed March 26, 1945, and scheduled for September 22, 1945, but was abandoned due to the strong opposition of Army Chief of Staff General Yoshijiro Umezu, who was also a member of Prime Minister Suzuki’s war cabinet.

The plan involved the use of five I-400 submarine aircraft carriers, each carrying three Aichi M6A Seiran floatplanes launched against San Diego, Los Angeles, and/or San Francisco. The aircraft were to spread bubonic plague, cholera, typhus, and dengue fever over the city, while the submarine crews infected themselves and ran ashore in a vast suicide mission.

Even after surrender, the Japanese considered a final use of biological weapons. Ishii wanted to stage suicide germ attacks against occupying U.S. troops in Japan. This planned attack never took place, once again due to opposition from General Umezu and Vice Chief of the Imperial Japanese Army General Staff, General Torashiro Kawabe, who claimed that he did not want Ishii to die in a suicide attack.

Almost as soon at World War II ended, a new Cold War began between the United States and the Soviet Union. In this atmosphere, Lt. Col. Murray Sanders of the United States Army recommended to General Douglas MacArthur and President Harry Truman in the fall of 1945 that Ishii and his subordinates be given immunity from prosecution as war criminals in return for Unit 731’s research.

MacArthur and Truman approved the deal, and Japan’s biological and chemical weapons program remained largely a secret until the 1990s.

From start to finish, the highest levels of the Japanese government and military were involved in Unit 731. Hideki Tojo, head of the Kempeitai in Manchuria from 1935 to 1937, became Japan’s longest serving prime minister in World War II, from October 18, 1941, to July 22, 1944. Tojo approved the attack on Pearl Harbor and was tried as a Class A war criminal and hanged in 1948.

General Yoshijiro Umezu, who served as the Army’s chief of staff, was a member of the elite war cabinet that held the reins of power in Japan from April 1945 until it surrendered to Allied forces on September 2, 1945. According to Lt. Gen. Kajitsuka Ryuji of the Japanese Medical Service and former Chief of the Medical Administration for the massive Kwantung Army (located in Manchuria), Ishii was given permission to begin the Ping Fang experiment in 1936 by “command of the Emperor.”

At some point in 1939-1940, Hirohito issued still another decree recognizing Ishii’s unit for its service. Moreover, the Emperor’s younger brother toured Unit 731’s facilities during its time of operation.

Unit 731 was extremely well funded, with state-of-the-art facilities, generously staffed with the cream of Japan’s medical community, and routinely communicated with the medical establishment back in Japan—which even provided suggestions for experiments and regularly received human samples.

The vast majority of Ishii’s staff walked away from their wartime service scot free. Information turned over to the United States proved worthless to the American biological weapons program, as the vivisection of human beings did not yield better scientific data.

Immune from prosecution as war criminals, many of Unit 731’s doctors went on to prominent careers in universities, hospitals, and industry, rising to positions that included governor of Tokyo, president of the Japanese Medical Association, and head of the Japanese Olympic Committee. The ringleader, Dr. Shiro Ishii, quietly returned to private practice and died in 1959 of throat cancer at the age of 67.

The Soviet Union was the only government to bring anyone associated with Unit 731 to trial. In late December 1949, in Khabarovsk, Russia, 12 former physicians, officers, and staff were accused of manufacturing biological and chemical weapons. While there was some coverage in the American press, the United States government, keen on protecting its secret deal, labeled the proceedings just another Soviet show trial.

It would take nearly 50 years before the infamy of Unit 731 came to light in the United States. Unlike the Nuremberg and Tokyo trials, in which high-ranking German and Japanese officials were hanged or sentenced to life in prison, the Khabarovsk trials saw no sentence exceed 25 years—with some as short as two. All of the defendants were quietly freed and slipped back to Japan by 1956.

In 1998, more than 100 Chinese plaintiffs filed suit in Japan in an effort to get the Japanese government to acknowledge the crimes of Unit 731 and to obtain reparations for the victims and their families. Mere months before the trial began, the Japanese Education Ministry approved a textbook glossing over the Imperial Japanese Army’s culpability.

The Tokyo District Court’s ruling, coming on August 28, 2002, accepted that Unit 731 had waged germ warfare in China and caused harm to residents but dismissed the Chinese plaintiffs’ claim for compensation. Nevertheless, it was the first time a Japanese court admitted that the Imperial Army had used biological weapons during its war with China from 1932-1945.

Judge Iwata said in handing down the ruling, “The evidence shows that Japanese troops, including those from Unit 731, used bacteriological weapons under the order of the Imperial Japanese Army’s headquarters and that many local residents died.” Noteworthy in the judge’s declaration was his understatement that “many local residents died.”

The judge’s comment was, however, consistent with much of the narrative written about Unit 731 after the war, which generally characterizes the group’s activities as “experimental,” a seeming reference to the vivisections conducted by the Japanese doctors.

Most accounts reckon the loss of life caused by vivisection to be around 3,000 to 10,000 individuals. These figures neglect the field tests of pathogens conducted against Chinese civilians and the subsequent losses of life from bubonic plague after the war.

Such minimization constitutes a miscarriage of justice for the hundreds of thousands who were murdered as a result of these attacks, and potentially the tens of thousands more Americans who could have died if the Japanese plans had been carried out on numerous Pacific battlefields, or if they had been successful in their attempts to deliver biological agents to the U.S. mainland in the latter stages of the war.

As it stands, Sheldon Harris’s Factories of Death (1994) estimates the loss of life at 200,000, with Daniel Barenblatt’s A Plague Upon Humanity (2008) putting it as high as 580,000.

At what point is Unit 731 indicted for mass murder? While some Japanese scholars have been rigorous in documenting Japan’s war crimes, their own government has been unwilling to acknowledge the atrocities it perpetrated against China.

Unit 731’s legacy is one of a useless, fanciful, extravagant, and sadistic indulgence that accomplished nothing politically or militarily for Japan, and, in terms of its research, nothing for the United States.

One can only hope that the perpetrators, who escaped prosecution as war criminals, achieved something positive in their postwar careers because the victims are still crying out for justice.

Back to the issue this appears in

Join The Conversation

Leave a reply cancel reply.

You must be logged in to post a comment.

Share This Article

• via= " class="share-btn twitter">

Related Articles

Felice Benuzzi’s Extraordinary Climb of Mount Kenya

Remembering a great leader on the 80th anniversary of Operation Overlord

A Burmese Jungle Masterstroke: Commonwealth Troops in Meiktila

Hazardous Duty with the Naval Armed Guard

From around the network.

Military History

The Siege of Shipka Pass

CSS Alabama vs USS Kearsarge: The Greatest High Seas Duel of the Civil War

A Flash of Sabers

The Battle of Kasserine Pass and the Failure of General Lloyd Fredendall

Advertisement

Inside Unit 731, Japan's Gruesome WWII Human Experiment Program

• Share Content on Facebook
• Share Content on LinkedIn
• Share Content on Flipboard
• Share Content on Reddit
• Share Content via Email

Key Takeaways

• Unit 731, a Japanese Imperial Army program, conducted deadly medical experiments and biological weapons testing on Chinese civilians during WWII.
• Thousands of prisoners were killed in cruel experiments, and perhaps hundreds of thousands more died from biological weapons testing.
• The true extent of Unit 731's actions was shielded from public knowledge for years, with the U.S. granting immunity to top officials in exchange for research.

For years after World War II , in most of what was considered the "civilized" world, the truth behind Japanese Imperial Army Unit 731 was quietly swept away. Facts were suppressed. Memories questioned. Reports denied.

Even today, the true extent of Unit 731's wartime actions — horrendous, deadly medical experiments and lethal biological weapons testing on unsuspecting Chinese civilians — is known largely only to historians and scholars.

But the facts are out there for those who seek them. And for those who seek to use them for their own personal reasons.

"I think that it has become a piece of this tortured dialogue over the war between Japan and China. The Chinese have seized upon this quite a bit. And the Japanese right, the nationalist right, their basic view is that, 'Oh, the Chinese. This is all political.' ... And there is a certain truth to that," says Daniel Sneider , a lecturer in international policy at Stanford's Freeman Spogli Institute for International Studies . "There is a 'uses of the past' question here. Perhaps you could say it's cynical in that everybody does it."

The truth is that Japan's Unit 731 committed some of the most heinous war crimes ever. Thousands of prisoners were killed in cruel human experiments at Unit 731, which was based near the northeastern China city of Harbin, north of the Korean peninsula and on a border with Russia. Perhaps hundreds of thousands more — maybe as many as a half-million — were killed when the Japanese tested their biological weapons on Chinese civilians.

The exact number of dead is not known. It may never be known.

"It's very difficult to calculate," says Yue-Him Tam , a history professor at Minnesota's Macalester College and co-author of a book entitled, " Unit 731: Laboratory of the Devil, Auschwitz of the East (Japanese Biological Warfare in China 1933-1945) ." Tam, born and raised in China, has taught a class at Macalester on war crimes and memory in contemporary East Asia for more than 20 years. "If you include those victims who suffered from the other activities — not necessarily just used as human guinea pigs — the bombs in China ... it's very difficult to calculate."

The Start of Unit 731

America's shameful part, dealing with unit 731 today.

Unit 731 — its official name was the Epidemic Prevention and Water Purification Department of the Kwantung Army — was formed before World War II began (at least for the U.S., which didn't officially enter the war until December 1941). It came about sometime in the mid-1930s when Japan and China went to war , a conflict that eventually morphed into World War II's war in the Pacific theater.

The Unit's charge was clear from the beginning: testing, producing and storing biological weapons. Such activities were outlawed by at least two international treaties at the time, though the Japanese did not ratify the 1925 Geneva protocol . It didn't matter.

From the start, Unit 731, under General Shirō Ishii , was merciless.

Among the thousands of experiments conducted on prisoners: vivisections without anesthesia; injections of venereal diseases to examine their spread; amputations to study blood loss; removal of other body parts and organs; starvation; and deliberate exposure to freezing temperatures to examine the effects of frostbite . From a 1995 article in The New York Times , relating a story from a medical assistant in Unit 731:

Reportedly, not one of the thousands of prisoners that were experimented on — most of whom were Chinese, though many were Russian or Korean — survived.

Later, the Japanese took especially virulent forms of the plague and other pathogens that were developed at Unit 731, put them in canisters and dropped them on nearby towns to see if their weapons would work. They did.

Thousands of these still-dangerous bombs remain in the Chinese countryside today, Tam says. Some people still suffer from the Japanese "dirty" bombs.

At one time, the Japanese hatched a plan to infect fleas with a plague manufactured at Unit 731 and drop flea-filled bombs, launched from planes stored aboard submarines, on San Diego in a mission code-named Operations Cherry Blossoms at Night . The war ended before the plan could be executed.

After the U.S. dropped atomic bombs on Japan and effectively ended the war in 1945, Japanese leaders ordered the destruction of Unit 731, which included more than 150 buildings and two airports. As the victorious Allied forces approached, many hundreds of remaining prisoners were killed. The thousands of people who worked in the place and conducted experiments on healthy, living humans scattered, many never to face justice.

The top doctors and soldiers at Unit 731 kept careful records of their experiments, and used them to leverage their way to freedom after the war. When the Allies swept into China, they agreed to grant Ishii and many of his associates immunity from prosecution for war crimes . The reasons: The U.S. wanted Unit 731's research for its own use , and it wanted to keep that information out of the hands of others, including the Russians. Thus, for years, the true nature of what went on in Unit 731 was shielded from public knowledge.

Some of the truth came out in the Khabarovsk War Crimes Trial , held in that Russian city in December 1949. Twelve members of Unit 731 and associated units were tried. All were found guilty and imprisoned. Despite that trial, though, much of what went on in Harbin was immediately classified by the U.S. government and remained clouded in secrecy.

More details about Unit 731 are still being unearthed. A confession from a unit commander, written to U.S. interrogators at a base in Maryland shortly after the war, was released in August 2021 by a Chinese provincial agency. Chinese and Russian news outlets heralded the release, which highlighted America's part in using the information gathered by Unit 731, hiding it and protecting its sources from further prosecution.

"The United States is not the outsider to this. Previously, I think the tendency was for the people in the United States to think, 'This is a problem between Japan and its neighbors.' But not only were we of course the major combatant in the war, we shaped the postwar settlement, including decisions like the one concerning Unit 731," Sneider says. "We made the big decisions about what was a war crime and what wasn't ... We're the creator of the postwar order, and therefore we have responsibility and involvement in dealing with the issues that were left, unfortunately, unresolved."

Research on 731 continues to be conducted all over the world. As recently as 2018, the Japanese government provided a list of more than 3,600 members of Unit 731 to a Japanese scholar. Yet even with more information, with politicians and the governments of various countries opening their records, the facts remain largely in the shadows and in some dispute.

In China, with the resurgent government now not as dependent on Japan as it was in the years following World War II, the Chinese are demanding more answers, eager to hold old rival Japan responsible.

For their part, most Japanese are not nearly as willing to engage in discussions about what is considered by many Japanese as a shameful period in that country's history. Some say the surge in Chinese interest in Unit 731 is nothing more than political in nature.

The U.S. is dealing with its own internal demons about its history with Unit 731.

These varying viewpoints, and others in the region and throughout the world, complicate matters. From 2006 to 2016, Sneider and others at Stanford's Walter H. Shorenstein Asia-Pacific Research Center conducted a project, " Divided Memories and Reconciliation ," aimed at examining the historical memory of the wartime period in Asia. These histories, viewed differently, go directly to ideas about national identity and nationalism. They are tricky histories to examine, uncovering differences that often stay unresolved.

"Sometimes the truth is pretty elusive," says Sneider. "To some degree, the goal is not necessarily always to establish 'the fact.' That's a good goal, but it may not be possible. The goal, if you're seeking reconciliation, the goal may be to understand the different perceptions of the other.

"In Japan, wartime memory is highly contested within Japan. They've been battling over these issues since 1945. Sometimes it's important just for Koreans and Chinese and Americans to understand what's going on within Japan. That path is contrived; to try to get to reconciliation by agreeing on what happened."

People may not agree on how many people were killed by the criminals in Unit 731, who did it, how it was done, or why it occurred. They can, and should, look critically upon America's decisions after the war, too.

But this much is indisputable: What happened in Unit 731 was an abomination.

In August 2015, The Museum of Evidence of War Crimes by Japanese Army Unit 731 opened in an area just south of Harbin, a city of more than 5 million people. Tam is among the millions who have visited the site.

"The room where they experimented with poisonous gas, there are still walls standing there, and the walls are really thick, almost like 1-meter [3.2-feet] thick, to prevent leaking of something. When I saw these things, I was really shedding tears as to how people can do that," Tam says. "It was very moving.

"I am a historian. The most important thing that matters to me is the facts. I want to find out the facts. And that was a fact, Unit 731. The crimes they committed and produced are facts."

Japanese war criminals were tried at the International Military Tribunal for the Far East , otherwise known as the Tokyo War Crimes trial. Testimony from Ishii , gathered in Maryland after his postwar arrest, was used in the trial, too. But Ishii, the architect behind the Unit 731 atrocities, was never charged. He died in Tokyo in 1959, a free man.

Frequently Asked Questions

How did unit 731's activities impact international laws on human experimentation, what were the long-term health effects on survivors of unit 731's experiments.

Please copy/paste the following text to properly cite this HowStuffWorks.com article:

ALLIANCE FOR HUMAN RESEARCH PROTECTION

Advancing Voluntary, Informed Consent to Medical Intervention

• Board of Directors
• Distinguished Advisory Board
• Honor Roll–Exemplary Professionals
• First, do no Harm
• Human Rights
• Informed Consent
• Nuremberg Code
• Discrimination
• Medicalized Racism
• Gene Modification
• Depopulation
• Technocracy
• Propaganda – Censorship
• Clinical Trials
• Concealed Data
• Public-Private Partnerships
• Pharma Corrupt Influence
• Publication Bias
• Organ Harvesting
• Bioweapon Experiments
• Transhumanism
• Current Medical Atrocities
• Japanese Atrocities
• Nazi Atrocities
• Operation Paperclip
• CIA Mind-Control
• CIA Torture
• U.S. Radiation Experiments
• Unethical Experiments
• Pandemic Control
• Great Reset
• Diabolical Lockstep
• Apartheid Policies
• Coronavirus Fear
• Covid Pandemic
• Government Overreach
• Vaccine Profit Engine
• Child Sacrifice
• Vaccine Mandates
• Vaccine Risks
• Vaccine Safety

December 10

1936–1945: Unit 731 — the Asian Auschwitz

Japanese Medical Atrocities

1936–1945: Unit 731 — the Asian Auschwitz — was a massive biological warfare research program of the Japanese Imperial Army under the command of Lt. General Dr. Ishii Shiro in Pin Fang, Manchuria outside the city of Harbin. Its true purpose was masked as the Epidemic Prevention Research Laboratory. Unit 731 was housed within 150 buildings with a staff of 3,000. It included an aerodrome, railway line, barracks, dungeons, laboratories, operating rooms, crematoria, cinema, bar and Shinto temple. Its barbarous inhumane experiments rivalled the infamous Nazi death camp of Auschwitz-Birkenau, though the numbers of prisoners were smaller, it operated for a much longer period. From 1936 to 1942 between 3,000 and 12,000 men, women and children were subjected to unspeakable diabolical experiments, vivisected while still alive, before they were slaughtered in Unit 731. (C. Hudson, Doctors of Depravity , 2007; Nightmare in Manchuria, 2012; Unit 731 )

Shiro Ishii’s extensive deadly human experiments were under the protection of the Kanto Army High Command, the Kampeitei (secret Japanese police), and local police collaborators. His first laboratories were in the city of Harbin, later in Beiyinhe, and still later in an extraordinary facility in Harbin’s suburb known as Ping Fang.  Construction began in 1936, and was completed in 1939. Originally named Togo, later changed to Ishii Unit, finally it was named Unit 731; it was the world’s largest premier biological and chemical warfare research center.

“Each year hundreds of prisoners were fodder for fiendish experiments.  They were exposed to every known disease.  These ranged from anthrax to yellow fever.  Some were used for hyperthermia experiments.  Others were forced to endure gangrene experiments; and still others were forced to engage in sexual intercourse with individuals known to be infected with venereal diseases. They were then monitored as the disease took its toll on the victims.” “The victims were captured communist partisans, ordinary criminals, political dissidents, those who were mentally handicapped but physically fit, and, when candidates among these groups were scarce, the secret police would pick up the poor, the homeless, off the streets in cities throughout occupied China and Manchuria.  The police would be given orders to send prisoners to Harbin/Ping Fan by “Special Delivery.” “Everyone engaged in this sordid business understood that “Special Delivery” was the code words for new human experimental prey.  Prisoners to be tested were of various nationalities.  The overwhelming majority were Han Chinese.  However, Koreans, Soviet prisoners of varying ethnic backgrounds, and, occasionally, Europeans and Americans were used.” “Victims were frequently vivisected while still living.  They were not given an anesthesia since Ishii and his colleagues wanted to be certain that their tests were not influenced by an outside source.  Those individuals whose experiments required a course of study usually lasted about six weeks.  Then, of no longer any value to the researchers, they were “sacrificed”, the euphemism used instead of “killed.”  The bodies, men, women, and children, would then be dissected by pathologists, and, eventually, deposited in either large burial pits or burned in the three crematoria housed at Ping Fan.” (Sheldon Harris. Japanese Medical Atrocities in WWII: Unit 731 Was Not An Isolated Aberration .” A paper read at the International Citizens Forum on War Crimes & Redress, Tokyo, Dec. 11, 1999)

Unit 731 was divided into eight divisions: Division 1: Research on bubonic plague , cholera , anthrax , typhoid and tuberculosis using live human subjects in a prison was constructed to contain around 300 to 400 people. Division 2: Research for biological weapons used in the field, in particular the production of devices to spread germs and parasites. Shiro Ishii, the mastermind behind Japan’s biological warfare — “Factories of Death” — was a brash and flamboyantly corrupt man who considered himself a visionary” beyond scruples. He was brilliant, charming, intimidating, stone-hearted, driven to break new scientific ground and to help Japan defeat its foes. Ishii exhorted his team of physicians to violate the physicians’ ethical code:

“A doctor’s God-given mission is to challenge all varieties of disease-causing micro-organisms; to block all roads of intrusion into the human body; to annihilate all foreign matter resident in our bodies; and to devise the most expeditious treatment possible. . . However, the research we are now about to embark is the complete opposite of these principles, and may cause us some anguish as doctors.” “We pursue this research,” he explained, “for the double medical thrill; as a scientist . . . probing to discover the truth in natural science; and as a military person, to build a powerful military weapon against the enemy.” (Patrick Fong. Impunity Of Japan’s Secret Biological Warfare Unit , 2000.)

Unspeakably cruel and ghoulish experiments were conducted by Japanese physicians who had been recruited from Japan’s leading academic medical institutions. Like their Nazi counterparts, Japan’s physicians perverted the essence of medicine. Doctors in the biological war program turned life – biology – against life.

They referred to the prisoners as Maruta (“logs” whose killing was comparable to cutting down a tree). Army surgeons conducted many vivisections “for training purposes” — in truth, to desensitize them. The victims were mostly Chinese — men, women, and children, including pregnant women and infants. Soviet, Australian and several American prisoners of war were also subjected to experiments designed to infect the victims with fatal diseases including: plague, cholera, tuberculosis, typhoid, tetanus, anthrax, typhus, hemorrhagic fever, and dysentery. See, list “medically usable specimens” (i.e., pathogens) compiled in a U.S. occupation report . The victims were then vivisected — many while still alive. Live vivisection was a Japanese “specialty.”

The experiments conducted at Unit 731 and its satellites can be classified into the following broad categories: Vivisections for training new Army surgeons: These were performed at army hospitals in China using many Chinese prisoners. The doctors were trained to perform appendectomies and tracheotomies; prisoners were shot, then doctors removed the bullets from their bodies; they amputated their arms and legs and sewed up the skin around the wounds, and finally killed the prisoners. This surgical training program was to teach newly minted army surgeons how to treat wounded soldiers at the front lines. However, unlike normal medical training which teaches surgical skills while avoiding causing harm to patients, the training of these army doctors encourages causing needless harm and death. So, it has been suggested that training under Unit 731 supervision, was not required at all, but rather its main purpose was to desensitize the surgeons, rather than to perfect their surgical skills. (Takashi Tsuchiya.  Why Japanese doctors performed human experiments in China 1933-1945 ,  Eubios Journal of Asian and International Bioethics, 2000)

Intentional infecting with viruses and pathogens followed by vivisection either after death or vivisected to death. Doctors purposefully infected victims with diseases ;  victims would then be strapped down to an operating table and subjected to live autopsy without anesthesia. Some screamed in a non-human way when they realized their fate. Unit 731 “doctors” would cut them open to observe the progress of the germs incubating within them or to harvest organs that had enough germs to weaponize or spread on nearby villagers. They would amputate limbs to study blood loss and the effects of rotting and gangrene (some limbs were later attached to the other side of the body), parts of the stomach, liver, brains and lungs were often removed to observe the effects. The reason for live vivisection was to study the effect of the pathogens on live human organs and to avoid decomposition.

Germ warfare , male and female prisoners were injected with venereal diseases in the disguise of inoculations (or sometimes infected via rape) to determine the viability of germ warfare, victims were infested with fleas in order to communicate the disease to an organism which could be later dropped onto a populace. During one anthrax operation, the doctors noted the progress of the pathogen organ by organ. The victim’s suffering was unspeakable, with “his organs swelling, bleeding and disintegrating.” Fleas were also tainted with cholera, anthrax, and the bubonic plague, as well as, other plagues. This was the origin of the “flea bomb” which infected large geographic areas and polluted land and water. They were dropped in the guise of clothing and supplies which resulted in the estimated death of another 400,000–580,000 Chinese civilians. (Read more: China History Forum , 2005.)

Weapons testing,  grenades, mortars and other explosive devices were detonated near living targets to determine the effects with regards to different distances and angles, so they could determine how long victims could survive with their sustained injuries; experiments to determine the ability of the human body to survive in the face of various pathogens and in conditions such as extreme cold; Chinese prisoners were exposed to mustard gas in a simulated battle situation; others were tied to stakes tests to determine the lethality of biological, and chemical weapons and other explosive material.

Physical endurance experiments,  to determine the physical tolerance level of human beings. The experiments were designed to answer questions such as: how much air could be injected intravenously; how much poison gas could be inhaled; how much bleeding caused death; how many days prisoners could survive without food or water; how high electric current human beings could bear; air pressurized, oxygen deprivation experiments — same as those conducted in Nazi concentration camps; frostbite experiments where prisoners would lose entire limbs and suffer gangrene; forced sex between prisoners (most often one that was infected with a STD while the other was healthy). In other experiments victims were hung upside down to observe how long it took for one to die due to choking and the length of time until the onset of embolism occurred after inserting air into ones blood stream. Read more: Unit 731

Nonstardized treatment tests and Sadistic what if? Experiments . Numerous experimental vaccines were tested on prisoners with no animal trials; Victims were hung upside down to observe how long it took for one to die due to choking; the length of time until the onset of embolism occurred after inserting air into ones blood stream; what would happen if horse serum got injected into the body of a human?

“Other experiments were conducted so the doctors could learn more about how humans live and die. These included studies of dehydration, starvation, frostbite, air pressure – some inmates had their eyes blown out – transfusions of animal blood to humans and others. Even children and babies were destroyed this way. Other ghoulish experiments included cutting off a prisoner’s hands and sewing them back on to the opposite arms to gauge what happened.” ( China History Forum , 2005)

Subscribe To Our Newsletter!

Sign up and be the first to find out the latest news and articles about what's going on in the medical field.

You may also like

November 21, 2023

Vera Sharav Joins Christine Anderson for Make It Your Business – Dec 4, 2023 in New Jersey

Vera Sharav is joining Christine Anderson as special guest for the Make It Your Business event in

Never Again is Now Global – Premiere Screening – Dec 1, 2023 in New York City

Vera Sharav is premiering the movie Never Again is Now Global in New York City, December 1.

National Museum of Nuclear Science & History

• World War II History

By Avani Sihra

In the 1930s-‘40s, the Japanese Empire committed atrocities across Asia, such as the Rape of Nanking. German crimes such as human medical testing committed in concentration camps tend to receive more attention than Japan’s crimes against humanity, as more research has been done and more historians have spent time looking back and studying these horrific acts. However, the Japanese too played a part in human medical testing in a secret project called Unit 731.

Begun in 1937, Unit 731, located in Harbin, China, was created with legitimate intentions by the Japanese government. Started as an agency to promote public health, Unit 731 was meant to conduct research that would benefit Japanese soldiers, such as learning more about the ways in which the human body can withstand hunger and thirst and fight diseases. Early experiments were conducted on volunteers who had signed consent waivers, giving personnel permission. However, as the war intensified, they changed their methods.

Although the 1925 Geneva Accords had banned the use of biological or chemical weapons in warfare, the Japanese nevertheless wanted to prepare for these types of warfare. As these types of experiments were naturally ones that most people would not volunteer to take part in, the Japanese decided to use prisoners of war as their test subjects. Unit 731’s victims who were primarily Chinese and Russians, along with some Mongolians and Koreans.

The leader of the unit was Lieutenant General Shiro Ishii. Along with the other scientists he recruited, they experimented by infecting test subjects with different types of diseases to see how their bodies would respond to pathogens. As the Japanese destroyed most of the Unit’s records at the end of the war, little is known about the scientists who worked there.

Using the test subjects, the scientists injected different germs to see how they would react to one another in the human body, in an attempt to create new diseases. Referring to their victims as Maturas , or “wooden logs,” Japanese scientists would perform different types of procedures, such as vivisection, on live victims. Rats infected with the bubonic plague were released onto victims, with the intention of infecting the subjects so that they could be studied. Unit 731 was a place of torture that was, in the minds of many Unit 731 workers, a necessity in order to win the war .

Scientists in Unit 731 also experimented on their test subjects through pregnancy and rape. Male prisoners infected with syphilis would be told to rape female prisoners as well as male prisoners in order to see how syphilis spreads in the body. Women were involuntarily impregnated and then experiments were done on them to see how it affected the mother as well as the fetus. Sometimes the mother would be vivisected in order to see how the fetus was developing. 

Once it was clear that the Japanese were going to lose the war, unit workers destroyed much of the evidence of the experiments. Upon the formal surrender of the Japanese in August 1945, Unit 731 was officially terminated. The Japanese government did not admit to the wrongdoing committed by Unit 731 until very recently. The government did not acknowledge the atrocity until 1988, and even then, they did not apologize for what had happened. The project was highly secretive and much of the evidence had been destroyed; in addition, government officials who were aware of what happened in Unit 731 did not make their knowledge known to the public. Because of this lack of acknowledgment, the Chinese government took it upon themselves to spread awareness of the atrocities. In 1982, they established a museum in the same place where Unit 731 operated during the war.

Unlike some of the Nazi doctors who conducted experiments on prisoners and concentration camp inmates, none of those involved with the experiments at Unit 731 were ever punished for their crimes. Instead, after war’s end, many re-entered society and went on to have very successful careers in their fields. American forces , chiefly General Douglas MacArthur, decided not to put workers of Unit 731 on trial. MacArthur granted those involved immunity in exchange for the information they had gathered while doing their experiments. He believed that pursuing trials against these people would get in the way of the Americans receiving the medical information that had been documented from these experiments. Because of this decision, justice was never served.

Frank, Richard B. Downfall. Penguin Books, 1994.

Kristof, Nicholas D. “Unmasking Horror -- A special report; Japan Confronting Gruesome War Atrocity.” New York Times, https://www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html . Accessed 3 May 2018.

Stockton, Richard. “Inside Unit 731, World War II Japan’s Sickening Human Experiments Program.” All That’s Interesting, http://allthatsinteresting.com/unit-731 . Accessed 3 May 2018.

Unit 731. Unit 731: Japan’s Biological Warfare Project, https://unit731.org/ . Accessed 3 May 2018.

• Search Menu

Sign in through your institution

• Advance articles
• Author Guidelines
• Submission Site
• Open Access
• Why Publish with JHMAS?
• About Journal of the History of Medicine and Allied Sciences
• Editorial Board
• Advertising and Corporate Services
• Self-Archiving Policy
• Dispatch Dates
• Terms and Conditions
• Journals on Oxford Academic
• Books on Oxford Academic

• < Previous

A Scientific Method to the Madness of Unit 731’s Human Experimentation and Biological Warfare Program

• Article contents
• Figures & tables
• Supplementary Data

Kishor Johnson, A Scientific Method to the Madness of Unit 731’s Human Experimentation and Biological Warfare Program, Journal of the History of Medicine and Allied Sciences , Volume 77, Issue 1, January 2022, Pages 24–47, https://doi.org/10.1093/jhmas/jrab044

• Permissions Icon Permissions

The Japanese Imperial Army Unit 731’s Biological Warfare (BW) research program committed atrocious crimes against humanity in their pursuit of biological weapons development during the Second World War. Due to an American cover-up, the details behind Unit 731’s human experimentation were slow to be revealed. The recent literature discloses the gruesome details of the experiments but characterizes the human trials as crude in nature. Further, there is a lack of clarity as to how human trial results were extrapolated for use in real world missions.

Through an examination of testimony from the Soviet Union’s Khabarovsk War Crime Trials, this paper argues that Unit 731’s inoculation and airborne warfare experiments on prisoners of war were scientifically rigorous. The scientific method is used as the basis against which the scientific rigor of the experiments is tested. The paper reveals that the successes and failures of the human trials were extrapolated to BW missions during the Sino-Japanese war. American researchers’ expectations of BW data were fulfilled, thus paving the way for an immunity deal. Ethical standards in medicine before WWII were not well established, but wartime medical practices and experimentation reveal the context in which the pursuit of scientific knowledge has no boundaries.

Personal account

• Sign in with email/username & password
• Get email alerts
• Save searches
• Purchase content
• Activate your purchase/trial code
• Add your ORCID iD

Institutional access

Sign in with a library card.

• Sign in with username/password
• Recommend to your librarian
• Institutional account management
• Get help with access

Access to content on Oxford Academic is often provided through institutional subscriptions and purchases. If you are a member of an institution with an active account, you may be able to access content in one of the following ways:

IP based access

Typically, access is provided across an institutional network to a range of IP addresses. This authentication occurs automatically, and it is not possible to sign out of an IP authenticated account.

Choose this option to get remote access when outside your institution. Shibboleth/Open Athens technology is used to provide single sign-on between your institution’s website and Oxford Academic.

• Click Sign in through your institution.
• Select your institution from the list provided, which will take you to your institution's website to sign in.
• When on the institution site, please use the credentials provided by your institution. Do not use an Oxford Academic personal account.
• Following successful sign in, you will be returned to Oxford Academic.

If your institution is not listed or you cannot sign in to your institution’s website, please contact your librarian or administrator.

Enter your library card number to sign in. If you cannot sign in, please contact your librarian.

Society Members

Society member access to a journal is achieved in one of the following ways:

Sign in through society site

Many societies offer single sign-on between the society website and Oxford Academic. If you see ‘Sign in through society site’ in the sign in pane within a journal:

• Click Sign in through society site.
• When on the society site, please use the credentials provided by that society. Do not use an Oxford Academic personal account.

If you do not have a society account or have forgotten your username or password, please contact your society.

Sign in using a personal account

Some societies use Oxford Academic personal accounts to provide access to their members. See below.

A personal account can be used to get email alerts, save searches, purchase content, and activate subscriptions.

Some societies use Oxford Academic personal accounts to provide access to their members.

Viewing your signed in accounts

Click the account icon in the top right to:

• View your signed in personal account and access account management features.
• View the institutional accounts that are providing access.

Signed in but can't access content

Oxford Academic is home to a wide variety of products. The institutional subscription may not cover the content that you are trying to access. If you believe you should have access to that content, please contact your librarian.

For librarians and administrators, your personal account also provides access to institutional account management. Here you will find options to view and activate subscriptions, manage institutional settings and access options, access usage statistics, and more.

Short-term Access

To purchase short-term access, please sign in to your personal account above.

Don't already have a personal account? Register

Email alerts

Citing articles via.

• Recommend to your Library
• Journals Career Network

Affiliations

• Online ISSN 1468-4373
• Print ISSN 0022-5045
• Copyright © 2024 Oxford University Press
• About Oxford Academic
• Publish journals with us
• University press partners
• What we publish
• New features  
• Open access
• Rights and permissions
• Accessibility
• Advertising
• Media enquiries
• Oxford University Press
• Oxford Languages
• University of Oxford

Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide

• Copyright © 2024 Oxford University Press
• Cookie settings
• Cookie policy
• Privacy policy
• Legal notice

This Feature Is Available To Subscribers Only

Sign In or Create an Account

This PDF is available to Subscribers Only

For full access to this pdf, sign in to an existing account, or purchase an annual subscription.

• History & Society
• Science & Tech
• Biographies
• Animals & Nature
• Geography & Travel
• Arts & Culture
• Games & Quizzes
• On This Day
• One Good Fact
• New Articles
• Lifestyles & Social Issues
• Philosophy & Religion
• Politics, Law & Government
• World History
• Health & Medicine
• Browse Biographies
• Birds, Reptiles & Other Vertebrates
• Bugs, Mollusks & Other Invertebrates
• Environment
• Fossils & Geologic Time
• Entertainment & Pop Culture
• Sports & Recreation
• Visual Arts
• Demystified
• Image Galleries
• Infographics
• Top Questions
• Britannica Kids
• Saving Earth
• Space Next 50
• Student Center

Learn about this topic in these articles:

World war ii: the horror of war in pictures.

Unit 731 of the Imperial Japanese Army carried out horrific medical experiments on thousands of prisoners of war and civilians; men and women were subjected to chemical and biological agents and vivisected to survey the results.

Watch CBS News

Mysterious skulls and skeletons unearthed 35 years ago could be linked to notorious war crimes, Japanese activists say

Updated on: July 26, 2024 / 8:10 AM EDT / CBS/AP

Depending on who you ask, the bones that have been sitting in a Tokyo repository for decades could be either leftovers from early 20th century anatomy classes, or the unburied and unidentified victims of one of the country's most notorious war crimes .

A group of activists, historians and other experts who want the government to investigate links to wartime human germ warfare experiments met over the weekend to mark the 35th anniversary of their discovery and renew a call for an independent panel to examine the evidence.

Japan's government has long avoided discussing wartime atrocities, including the sexual abuse of Asian women known as "comfort women" and Korean forced laborers at Japanese mines and factories, often on grounds of lack of documentary proof. Japan has apologized for its aggression in Asia, but since the 2010s it has been repeatedly criticized in South Korea and China for backpedaling.

Around a dozen skulls, many with cuts, and parts of other skeletons were unearthed on July 22, 1989, during construction of a Health Ministry research institute at the site of the wartime Army Medical School. The school's close ties to a germ and biological warfare unit led many to suspect that they could be the remains of a dark history that the Japanese government has never officially acknowledged.

Headquartered in then-Japanese-controlled northeast China, Unit 731 and several related units injected prisoners of war with typhus, cholera and other diseases, according to historians and former unit members. They also say the unit performed unnecessary amputations and organ removals on living people to practice surgery and froze prisoners to death in endurance tests. Japan's government has acknowledged only that Unit 731 existed.

Led by Gen. Shiro Ishii, Unit 731 researchers "used men and women as involuntary test subjects, causing them unspeakable pain and suffering as they were injected with germs, fed infected foods, and bitten by rodents and fleas," according to the U.S. Naval Institute .

The institute said Unit 731 also produced devices to poison individuals with fountain pens and pointed walking sticks, as well as "techniques for clandestinely poisoning drinking wells." The unit also developed a bomb "that could destroy vegetation in an area of 20 square miles" and experimented with artillery shells carrying gas and biological agents, the institute said.

Top Unit 731 officials were not tried in postwar tribunals as the U.S. sought to get ahold of chemical warfare data, historians say.

"Perhaps the most notorious was Gen. Ishii of Unit 731, who escaped postwar prosecution in exchange, apparently, for supplying the U.S. government with details of his gruesome human experiments," historian Edward Drea wrote in an essay published by the U.S. Archives .

Lower-ranked officials were tried by Soviet tribunals. Some of the unit's leaders became medical professors and pharmaceutical executives after the war.

"We just want to find the truth"  

A previous Health Ministry investigation said the bones couldn't be linked to the unit, and concluded that the remains were most likely from bodies used in medical education or brought back from war zones for analysis, in a 2001 report based on questioning 290 people associated with the school.

It acknowledged that some interviewees drew connections to Unit 731. One said he saw a head in a barrel shipped from Manchuria, northern China, where the unit was based. Two others noted hearing about specimens from the unit being stored in a school building, but had not actually seen them. Others denied the link, saying the specimens could include those from the prewar era.

A 1992 anthropological analysis found that the bones came from at least 62 and possibly more than 100 different bodies, mostly adults from parts of Asia outside Japan. The holes and cuts found on some skulls were made after death, it said, but did not find evidence linking the bones to Unit 731.

But activists say that the government could do more to uncover the truth, including publishing full accounts of its interviews and conducting DNA testing.

Kazuyuki Kawamura, a former Shinjuku district assembly member who has devoted most of his career to resolving the bone mystery, recently obtained 400 pages of research materials from the 2001 report using freedom of information requests, and says it shows that the government "tactfully excluded" key information from witness accounts.

The newly published material doesn't contain a smoking gun, but it includes vivid descriptions - the man who described seeing a head in a barrel also described helping to handle it and then running off to vomit - and comments from several witnesses who suggested that more forensic investigation might show a link to Unit 731.

"Our goal is to identify the bones and send them back to their families," said Kawamura. The bones are virtually the only proof of what happened, he says. "We just want to find the truth."

Health Ministry official Atsushi Akiyama said that witness accounts had already been analyzed and factored into the 2001 report, and the government's position remains unchanged. A key missing link is a documentary evidence, such as a label on a specimen container or official records, he said.

Documents, especially those involving Japan's wartime atrocities, were carefully destroyed in the war's closing days and finding new evidence for a proof would be difficult.

Akiyama added that a lack of information about the bones would make DNA analysis difficult.

Hideo Shimizu, who was sent to Unit 731 in April 1945 at age 14 as lab technician and joined the meeting online from his home in Nagano, said he remembers seeing heads and body parts in formalin jars stored in a specimen room in the unit's main building. One that struck him most was a dissected belly with a fetus inside. He was told they were "maruta" - logs - a term used for prisoners chosen for experiments.

Days before Japan's Aug. 15, 1945 surrender, Shimizu was ordered to collect bones of prisoners' bodies burned in a pit. He was then given a pistol and a packet of cyanide to kill himself if he was caught on his journey back to Japan.

He was ordered never to tell anyone about his Unit 731 experience, never contact his colleagues, and never seek a government or medical job.

Shimizu said he cannot tell if any specimen he saw at the 731 could be among the Shinjuku bones by looking at their photos, but that what he saw in Harbin should never be repeated. When he sees his great-grandchildren, he said, they remind him of that fetus he saw and the lives lost.

"I want younger people to understand the tragedy of war," he said.

• World War II

More from CBS News

Strikes in Gaza and fatal stabbing in Tel Aviv spike fears of wider war

Attack at Somalia beach hotel by al-Qaeda-linked group kills at least 32

U.S. women's soccer team narrowly beat Japan in Olympics quarterfinals

Mayor arrested for alleged sex with minor days after she resigned

• Instant Articles
• Warfare History

The True Story Behind Japan’s WWII Human Experiment Division

The 20th Century is full of examples of man’s inhumanity to man. The horrors of the first World War early in the century set the stage for what was to become one of the darkest periods in human history. And no event serves as a more terrible reminder of how evil people can be than the atrocities that followed in the second World War.

The crimes of Nazi Germany in occupied territories and the industrial slaughter of the Holocaust resulted in the deaths of millions of people. But the second World War was truly a global conflict and evil was found everywhere it was fought.

Though they often get less popular attention than those of the Germans, the Japanese military’s crimes were certainly horrific. The occupation of Nanking by the Japanese Army led to a maelstrom of violence that lead to tens or possibly even hundreds of thousands of deaths among the residents of the city.

Like the Germans, the Japanese often treated the citizens in occupied territories with almost casual cruelty. Also like the Germans, the Japanese even exploited these people for horrific human experimentation . They even had a specialized unit they created to conduct these experiments: Unit 731.

The story of Unit 731 really began before the Second World War with the person who would eventually lead the unit’s activities, Shiro Ishii . Ishii was a medical officer in the Japanese military who specialized in studying infectious diseases. This kind of research was a popular subject for Japanese Army researchers like Ishii, who realized the importance of keeping troops healthy in the field. But Ishii also realized that infectious diseases could be turned against an enemy’s troops and began to advocate that the military look into developing biological weapons.

In 1930, Ishii petitioned the government for funding to form a research team that would study the effects of pandemic diseases. The government agreed and Ishii began work at the “Epidemic Prevention Research Laboratory,” where he claimed publicly to be working on ways to protect Japanese troops from diseases. This was actually true in one sense. Much of Ishii’s work was dedicated to researching effective ways to treat and prevent infectious diseases. However, Ishii’s actual intentions were always far darker. He wanted to learn which diseases would be the best candidate for weaponization.

With the permission of his direct superiors in the military, Ishii began to look for ways to turn his knowledge of preventing diseases towards finding ways to spread them. Ishii began testing various diseases on animals to see which spread quickly and killed efficiently in the hopes of finding the perfect biological weapon . However, Ishii felt that what he really needed to achieve his goal were human subjects. Because his research unit operated in Tokyo, ethical concerns and fears of containing the diseases he was testing prevented him from acquiring these subjects. However, events would soon provide him with the opportunity he needed.

NEXT >>

In 1931, a Japanese military officer placed dynamite near the tracks of a Japanese-owned railway line in the region of Manchuria in North-East China. The resulting explosion did little actual damage, but officers in the Japanese Army seized the opportunity and blamed Chinese saboteurs for the attack that they themselves had engineered. Using the event as a pretext, they launched an invasion, quickly taking control of the region from the Chinese. The Chinese government, which didn’t want a war with Japan, offered little resistance and Japan set up a puppet government under the last Qing Emperor of China, Puyi .

Shiro Ishii recognized the opportunity to collect subjects from the civilian population of Manchuria and moved to Zhongma Fortress near the city of Harbin in Manchuria. There, Ishii organized a secret research group called the “Togo Unit” and began his research in earnest. During the occupation, the Japanese Army and secret police frequently arrested Chinese civilians and resistance fighters, as well as common criminals. Many of these prisoners ended up in Zhongma fortress, where they fell under the control of Ishii and the Togo Unit.

Ishii began to test the effects of various diseases on his human subjects. Under the guise of giving them vaccines, prisoners were injected with different bacteria or viruses to see how long it took for them to become infected. After the infection set in, the prisoners were monitored to see how the disease developed compared to other prisoners. In many cases, prisoners were then cut open while still alive to study the effects of the disease on their internal organs. Those who didn’t die from these tests were executed.

In 1934, a prisoner at Zhongma managed to overpower a guard and take his keys. He then freed forty of his fellow prisoners and scaled the walls of the fortress. Many of the prisoners attempting to escape were shot or recaptured, but a few managed to get away and spread the word of what was going on inside the prison. This escape and loss of secrecy lead Ishii and his superiors to close down their research at Zhongma and move to a new facility. There, the unit acquired the name by which it is most well-known: Unit 731. And there, they continued their horrific experiments.

Unit 731 was able to continue getting its supply of fresh subjects through the Japanese secret police, the Kempeitai. The Kempeitai arrested Chinese civilians on trumped-up charges of “suspicious activities” at the behest of Unit 731, which gave them instructions on whom to arrest. Ishii wanted to make sure that his subjects reflected the general population, so pregnant women, children, and the elderly were all arrested on these sorts of charges and brought to Ishii’s facility for tests on the effects of different diseases. And because Ishii wanted to test the effects of disease on different races of people, the large Russian community in Harbin was frequently targeted by the Kempeitei. In Ishii’s eyes, everyone was a potential subject for his twisted experiments.

<< Previous

Ishii’s goal was always to find an effective biological weapon, so he investigated some of the most virulent diseases in human history. Many of his tests focused on the bubonic plague , which killed millions during the Middle Ages. He wanted to find ways to spread the plague quickly, which meant testing the best way to infect large numbers of people with the disease. Ishii ordered plague-infected fleas to be dropped from airplanes onto cities in China, leading to minor epidemics that killed thousands. In addition to fleas, Unit 731 dropped clothing or food infected with cholera and anthrax, leading to more epidemics and thousands of deaths.

But Unit 731 didn’t limit its research to just weaponizing disease, they also tested the effects of different injuries to the human body. Prisoners were often subjected to freezing temperatures to study the effects of frostbite, as guards beat them to determine how much feeling was left in their frozen limbs. The injuries were then left untreated to study the effects of gangrene, as the prisoner’s fingers or limbs began to rot and fall off. Other prisoners were subjected to experiments testing the effects of grenades from different ranges, and even flamethrowers. Obviously, few survived these types of tests.

Unit 731 was also very interested in venereal diseases, like syphilis or gonorrhea. Often, prisoners were infected with these diseases to test the effects and treatments. But these prisoners were also forced under threat of death to have sex with uninfected prisoners so that researchers could study how the diseases were transmitted from one person to another. They also wanted to study whether or not pregnant women could transmit a venereal disease to their fetus; thus women were sometimes forcibly impregnated for these tests.

Prisoners were also subjected to stranger experiments that reflect the callous disregard for human life shown by Unit 731. It was as though they simply wanted to satisfy their morbid curiosity. Prisoners were strapped into centrifuges that spun them at high speeds until they died. Others were injected with animal blood or seawater, simply to see how their body might respond. Still, others were bombarded with X-rays to study the effects of radiation. Some were simply buried alive or burnt to death. And others were denied food or water to see how long it took them to die.

Ultimately, Ishii’s experiments accomplished little. The Japanese never managed to develop a biological weapon that could turn the tide of the war. And Ishii’s attempts to pressure the Japanese military to use biological weapons in the Pacific were rebuffed several times. The only serious attack ever planned was to target the city of San Diego. However, this last desperate plan was aborted due to Japan’s surrender in 1945. After the surrender, Ishii was granted immunity by the American occupation forces in exchange for handing over his research. Ishii never stood trial for his crimes and lived out the rest of his days in Japan before dying of throat cancer years later. The fact that Ishii and other members of Unit 731 escaped prosecution truly rank among the worst failures of justice in history.

Dangerous World

Understanding Existential Risks

Unit 731: Imperial Japan’s Biological and Chemical Warfare

Written by Romeo Jung.

Introduction

Unit 731 was a secret Biological and Chemical Warfare Unit that Imperial Japan had established during the World War II. Eager to win the war, the scientists involved committed a lot of inhumane crimes like vivisection to Chinese, Korean, Russian, and Mongolian prisoners of war, and used the data gained to harm many Chinese civilians. This essay details heavily on the biological research and its data from start to the end as well as their impacts and aftermath.

Unit 731 was established first in 1932 as a small group of five scientists interested in biological weapons, and was expanded around 1936 when Shiro Ishii was given full command of the unit. Given alternative names like “lumber yard” and “Epidemic Prevention and Water Purification Department of the Kwantung Army”, the name “Unit 731” was made formal in 1941.  The lab was based at the Epidemic Prevention Research Laboratory in Japanese Army Military Medical School in Tokyo. Their purpose was none of the given names, but biological and chemical warfare research.

The idea of Unit 731 first circulated around by a memo written in April 23, 1936, that speaks about the establishment of reinforcement military forces in Manchuria. The memo states that there would be a new “Kwantung Army Epidemic Prevention Department” and that it shall be expanded later on. 

The headquarters was set in three square kilometers of land in Pingfang district, Manchuria. Many of the lab’s buildings inside were hidden by a tall wall and high voltage wired fences. The lab had around 150 buildings, including incinerator, housing for prisoners, an animal house, and air field. The buildings were completely isolated from the outside world, with only a tunnel as the entrance.

Unit 731, along with two other units to be mentioned later, was created in opposition to the Geneva protocol of 1925 banning biological and chemical warfare. This protocol was signed at June 17, 1925 in Geneva. It became effective from February 8th, 1928, and got registered by League of Nations Treaty Series on September 7, 1929.

Within Unit 731, there were eight subunits designed to focus on different topics of warfare. The first division focused on biological weapons like bubonic plague, cholera, anthrax, typhoid, and tuberculosis, with human subjects to work with. The second division  focused on effectively spreading the biological weapons covered in the first division. The third division was focused on a specific way of spreading biological agents by bomb, the fourth on bacteria mass production and storage. The fifth through eighth divisions  were mostly focused on the supplying the rest of the Unit, which included training workers, providing equipment, and overall administrative units.

Outside of Unit 731, Japan established two departments: Unit 100 and Unit 516. Unit 100 was first declared as the “Kwantung Army Military Horse Epidemic Prevention Workshop,” which focused on developing biological weapons aside from Unit 731. “Kwantung Army Technical Testing Department”, later called Unit 516, was also established for more research that focused on chemical weapons. 

People Involved

There were many involved with the research of Unit 731, most of them remaining anonymous to this day. Shiro Ishii was the Chief of Unit 731, with Masaji Kitano as second in command. Other scientists were most likely to be a Professor at an university or a chief of a medical research unit, like Dr. Hisato Yoshimura, who directed the frostbite experiments on subjects, and Dr. Hideo Futaki, who lead the tuberculosis research squad and some vivisections. Other personnels include Lieutenant Shunichi Suzuki, who, after the trials, went to work as the Governor of Tokyo, and Amitani Shogo, who remained at the lab afterwards and received the Asahi Prize for outstanding scientific performance.

Shiro Ishii served in the Imperial Japanese Army from 1921 to 1945, and in the meantime, he was a Japanese army medical officer, microbiologist, and the director of Unit 731. Before serving in the army, he had studied medicine at Kyoto Imperial University. He was first assigned as an army surgeon, then to the First Army Hospital and Army Medical School in Tokyo. His work soon impressed the superiors, which earned him postgraduate level medical education. Ishii was promoted to an army surgeon in 1925, and was advocating for a biological weapons research program.

After getting promoted to higher ranks, Ishii began his experiments in Zhongma Fortress for biological weapons. Then the government granted him permission to set up Unit 731 in his hopes of digging deeper into the topic. After World War II, he was arrested for a short time by the US occupation authorities for Unit 731, then received immunity from consequences in exchange for data. There are different accounts as to what he did after that, but some say that he traveled around to give talks about biological weapons and others say that he stayed in Japan to provide medical services for free.

What They Did

In Unit 731, the first division conducted many outrageous experiments which were violating human rights. They conducted   many experiments that tested the limitations of the human body. The prisoners, used as subjects, were of mixed ethnicity and gender, some pregnant, and some as young as three years old.  The prisoners, tied to stakes, would have to endure the biological agent bombs that carried plague infested fleas on them or rats with the diseases. Then they were subject to their body being cut open with a scalpel and examined while they were screaming for mercy on the table. 

An unnamed Unit 731 surgeon, in an interview with  New York Times, described his experience with the unit. His first vivisection, which he recalled that he “cut [the prisoner] open from the chest to the stomach, and he screamed terribly, and his face was all twisted in agony… …finally he stopped. This was all in a day’s work for the surgeons…” (Kristof) There was no use of anesthetics during vivisections at all because they were afraid that it would have an effect on the results and data.

In another part of his article, Kristof interviews a former medical worker in Unit 731, Takeo Wano. Wano says that he had seen “six-foot-high glass jar in which a Western man was pickled in formaldehyde. The man had been cut into two pieces, vertically.” There were many other jars in the headquarters of Unit 731 containing other body parts from different people, labeled often as their ethnicity. An anonymous Unit 731 veteran says that most of the jars had been noted as Chinese, Korean, and Mongolian, although there were occasionally American, English, and French. Some body parts were even sent in from other places.

Other experiments included prisoners being locked inside a pressure chamber to test how much pressure the body can handle before their eyes started popping out, being exposed to poisonous gas and many more biological and chemical weapons, having limbs cut off for studying blood loss, having cut off limbs attached to different parts of the body, having horse urine injected into kidneys, and having lethal dosages of x-rays. Kristof noted that “The accounts are wrenching to read even after so much time has passed: a Russian mother and daughter left in a gas chamber, for example, as doctors peered through thick glass and timed their convulsions, watching as the woman sprawled over her child in a futile effort to save her from the gas.”

Hisato Yoshimura, apart from infection based experiments, led the frostbite experiments, which focused on the effects of frostbite on human limbs. He gave orders to freeze limbs of prisoners, often until they were black. The prisoners were let in only when an officer was sure that their limbs were frozen. The officers would test limbs by beating them with a stick, as they knew that frozen limbs sound like wooden boards upon hitting. 

After chilling prisoners’ limbs to near 0 degrees Celsius with ice water, Yoshimura continued to chop off parts of the limb, especially fingers, so that he may record how the frostbite was affecting human limbs. He and his team experimented on subjects as young as three years old, with a needle in their finger to keep it from clenching into a fist. 

Effects During War

The Japanese Military used the biological weapons developed by Unit 731 directly on Chinese civilian population. Agents in divisions other than the first division in Unit 731 would spread the diseases by train, road, and airplanes. Many Chinese civilians developed the worst infections on their limbs, and only a few were exposed to treatment since no local doctors or hospitals had seen the infections before.

Quzhou village, Ya Fan village, and Chong Shan village in the Zhejiang Province had suffered deeply from the Bubonic Plague, as well as Dysentery, Typhoid, Cholera, and many more. In an episode of BBC Correspondent,  Wu Shi-Gen, a victim of Unit 731’s biological weapons, tells his story of how the Bubonic Plague had affected his nine-year old brother. The rest of the family chose to lock his little brother away in another room to minimize the possibilities of infections while the little boy cried out from the room. Wu said he still remembers how he could not run in and help his brother when he cried out in pain.

Ya Fan village was affected with an unknown infection, commonly known to residents as “The Rotten Leg Disease.” A victim of this infection describes it as something that “started like an insect bite, then swelling and unbearable pain. Then his flesh started rotting away. Many died of it. Experts say it’s probably Glanders, another of Unit 731’s special recipes. Treatments were ineffectual and cost a fortune.” He stated that while his mother and he both had the disease on their legs, she refused the medicine so that he could have it instead of her. She passed away a few months later.

Aside from negative effects, Unit 731’s research was also used to heal Japanese soldiers with certain conditions. Studying about human conditions like frostbites and different diseases, the doctors could effectively pinpoint medical solutions for their sick soldiers. For instance, the frostbite experiment revealed that putting frozen limbs in water from 100 to 122 degrees Celsius is the best.

As soon as the World War II was over, the scientists at Unit 731’s headquarters started burning the building down, getting rid of all the evidence. When Shiro Ishii and many others were captured by China and sent over to the US for a trial, they had a deal with President MacArthur. He decided to let go of the Unit 731’s scientists free of charge for the war crimes in exchange for their medical research data.

In addition, Japanese government was fairly late to apologize to the rightful victims of Unit 731, while paying war tributes to the dead war criminals of Unit 731. They have been continuously visiting their shrines every year since 2013, offending neighboring countries and victims. Many news articles had been written about it, yet they do not seem to matter to the Japanese government.

Many Japanese scholars also deny the fact that there was ever a Unit 731 and state that the history involving the group is fabricated, although there are plenty of evidences. The Japanese history textbooks do not cover most of Japan’s horrific acts in World War II, leading them to believe that Japan was mostly a victim country rather than hostile like their opponents. By large, the Japanese public has a false sense of history due to the fact that their history textbooks are skewed. 

The former members of Unit 731 seem to have conflicting opinions about the publicity of the topic. Yoshio Shinozuka and some others had gone to give talks and share information about Unit 731, but others like Toshimi Mizobuchi intend to keep the promise to hide the information. A portion of Unit 731 members still hold their annual staff reunion parties hosted by Mizobuchi.

Unit 731 has been one of of the most cruel groups to do human experimentation, yet so few people that I’ve met know about what really happened. Although these inhumane experiments could be defended by saying that they were useful for modern medical science, they were definitely not worth the cost of many civilian lives as well as prisoners’ suffering.

Maruta — “Log” in Japanese. Prisoners were often called logs so that they could be experimented on without scientists feeling remorse.

Vivisection —  Much like dissection, but with an alive person.

Unit 731: Japan’s Biological Warfare Project. (2018). Retrieved March 14, 2018, from https://unit731.org/ Kristof, N. D. (1995, March 17). Unmasking Horror — A special report.; Japan Confronting Gruesome War Atrocity. Retrieved March 24, 2018, from https://www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html?pagewanted=all L. (2013, February 11). Unit 731: Japan’s biological force. Retrieved March 24, 2018, from https://www.youtube.com/watch?v=8LfMNX3TsT0 Working, R. (2001, June 5). The trial of Unit 731. Retrieved March 24, 2018, from https://www.japantimes.co.jp/opinion/2001/06/05/commentary/world-commentary/the-trial-of-unit-731/#.WqoQ6z9zJhE McCurry, J. (2013, December 26). Japan’s Shinzo Abe angers neighbours and US by visiting war dead shrine. Retrieved March 24, 2018, from https://www.theguardian.com/world/2013/dec/26/japan-shinzo-abe-tension-neighbours-shrine Beijing, S. A. (2014, October 17). China protests at Japanese PM’s latest WW2 shrine tribute. Retrieved March 24, 2018, from https://www.theguardian.com/world/2014/oct/17/china-protests-japan-shinzo-abe-yasukuni-shrine Japanese PM Abe sends ritual offering to Yasukuni shrine for war dead. (2017, October 17). Retrieved March 24, 2018, from https://www.reuters.com/article/us-japan-yasukuni/japanese-pm-abe-sends-ritual-offering-to-yasukuni-shrine-for-war-dead-idUSKBN1CL355 Abe training jet photo sparks outrage in South Korean media. (2013, May 15). Retrieved March 24, 2018, from http://www.scmp.com/news/asia/article/1238533/abe-training-jet-photo-sparks-outrage-south-korean-media Tsuneishi, K. (2005, November 24). Unit 731 and the Japanese Imperial Army’s Biological Warfare Program. Retrieved March 24, 2018, from https://apjjf.org/-Tsuneishi-Keiichi/2194/article.html Pure Evil: Wartime Japanese Doctor Had No Regard for Human Suffering. (2016, June 15). Retrieved March 24, 2018, from https://www.medicalbag.com/despicable-doctors/pure-evil-wartime-japanese-doctor-had-no-regard-for-human-suffering/article/472462/ Tsuchiya, T. (2007, December 16). Retrieved March 24, 2018, from http://www.lit.osaka-cu.ac.jp/user/tsuchiya/gyoseki/presentation/UNESCOkumamoto07.html Unit 731: One of the Most Terrifying Secrets of the 20th Century. (n.d.). Retrieved March 26, 2018, from https://www.mtholyoke.edu/~kann20c/classweb/dw2/page1.html

Share this post:

Leave a reply cancel reply.

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

• Terms of Use

War News | Military History | Military News

Japan’s dr. mengele: medical experiments on pow’s at unit 731.

• World War 2

The main site of Japan’s experiments into biological warfare was the prisoner of war camp known as Unit 731 located in Pingfan, Manchuria, where Chinese inmates were subjected to gruesome experiments aimed at testing the limits of the human body and the effectiveness of biological and chemical agents.

These experiments were replicated elsewhere on Allied POWs in the puppet state of Manchukuo created by the Japanese and nominally ruled by Pu Yi, the last emperor of China.

Shiro Ishii, a Japanese Doctor Mengele

Born on 25th June 1892, Shiro Ishii was a brilliant medical student at the Imperial University in Kyoto who then went on to become a surgeon in the Imperial Guard. Further studies cemented Ishii’s status as one of the country’s pre-eminent specialists in the field of bacterial research and he is credited with inventing a revolutionary filtration system which could remove all traces of bacteria from stagnant water.

From 1933, Ishii switched his attention away from the prevention of infections and began to concentrate his research on how dangerous bacterium could be best employed in warfare.

Unit 731, the Center of Japan’s Wartime Experiments on Humans

In 1933, Shiro Ishii moved his team of researchers to Manchuria in China and assumed leadership of a center of experimentation into biological warfare which would later come to be known as Unit No. 731, and eventually be responsible for the deaths of around 3,000 inmates.

The human guinea pigs of Unit 731 were mostly captured Chinese soldiers or locals thought hostile to the occupation. However, at the nearby camps of Hogoin and Moukden similar experiments were repeated on captured Russian and other Allied soldiers respectively. The results were then transmitted back to Ishii’s personnel for verification.

Inmates of the camps were subjected to a terrifying array of experiments. Bombs containing gangrene or various bacterium were set-off in close proximity to prisoners, not with the intention of causing death by explosion, but in order to study the effectiveness of airborne infection.

Among many other atrocities, subjects were exposed to extremes of temperature, decompression, bombarded by x-rays, starved, deprived of sleep, boiled alive, killed in giant centrifuges, or even subjected to vivisection whilst still alive.

The Aims of Unit 731 and Shiro Ishii’s Research

The horrific experiments carried out within the walls of Unit 731 were not just a case of cruelty for cruelty’s sake. The aim of Shiro Ishii’s research was the development of an effective chemical and biological weapons program that could turn the tide of the war in Japan’s favor.

Shiro Ishii was particularly interested in the plague and a significant amount of Unit 731’s resources were expended on breeding rats to sustain plague-carrying fleas.

Several outbreaks of plague in China during the early 1940s can be directly attributed to Ishii’s experiments on the local populace. When running at full capacity, Unit 731 was theoretically capable of producing three hundred kilos of plague germs per month and enough bacteria of various sorts to kill the entire population of the world several times over.

The End of Unit 731 and the War Crimes Tribunals

In August 1945, as the Soviet army swept into Manchuria, Shiro Ishii evacuated around 2,000 members of Unit 731 back to Japan; everyone was under strict instructions to separate and not to talk to anyone of what had happened at the camp.

The retreating Japanese army destroyed nearly all traces of Unit 731 and other similar camps, although some documents still fell into Soviet hands and were used to set up their own programs after the war. At Unit 731 alone, the Japanese army killed all of the prisoners and machine-gunned six hundred local workers.

Once Japan had formally surrendered, Shiro Ishii and others deemed responsible for carrying out atrocities in the pursuit of biological warfare were regularly interrogated by the Americans, who refused all Soviet requests to hand them over.

Shiro Ishii never faced a war crimes tribunal, and the subject of biological warfare was never raised during any of the trials of suspected Japanese war criminals. General MacArthur himself officially denied the existence of any Japanese experiments on American soldiers.

The reason for this is simple: a deal had been struck whereby Ishii told the Americans everything he knew about biological and chemical warfare in return for immunity from prosecution.

Shiro Ishii died of throat cancer in 1959 but the last years of his life are the subject of some dispute: it is claimed that he continued his research into biological warfare in America, but his daughter denies this and asserts that he spent the post-war period in Japan.

The Twisted Story Of Shiro Ishii, The Josef Mengele Of World War 2 Japan

Shiro ishii ran unit 731 and performed cruel experiments on prisoners until he was apprehended by the u.s. government — and granted full immunity..

A few years after World War I, the Geneva Protocol prohibited the use of chemical and biological weapons during wartime in 1925. But that didn’t stop a Japanese army medical officer named Shiro Ishii.

A graduate of Kyoto Imperial University and a member of the Army Medical Corps, Ishii was reading about the recent bans when he got an idea: If biological weapons were so dangerous that they were off-limits, then they had to be the best kind.

Wikimedia Commons Shiro Ishii is often compared to the infamous Nazi doctor Josef Mengele, but he arguably had even more power over his human experiments — and did far more monstrous scientific research.

From that point on, Ishii dedicated his life to the deadliest kinds of science. His germ warfare and inhumane experiments aimed to place the Empire of Japan on a pedestal above the world. This is the story of General Shiro Ishii, Japan’s answer to Josef Mengele and the evil “genius” behind Unit 731.

Shiro Ishii: A Dangerous Youth

Born in 1892 in Japan, Shiro Ishii was the fourth son of a wealthy landowner and sake maker. Rumored to have a photographic memory, Ishii excelled in school to the point that he was labeled a potential genius.

Ishii’s daughter Harumi would later muse that her father’s intelligence might have led him to be a successful politician if he had chosen to go down that path. But Ishii chose to join the military at an early age, showing boundless love for Japan and its emperor all along the way.

Wikimedia Commons From an early age, Shiro Ishii was believed to be a genius.

An atypical recruit, Ishii did well in the military. Standing six feet tall — well above the height of the average Japanese man — he boasted a commanding appearance early on. He was known for his spotlessly clean uniforms, his meticulously groomed facial hair, and his deep, powerful voice.

During his service, Ishii discovered his real passion — science. Specifically interested in military medicine, he worked tirelessly toward the goal of becoming a doctor in the Imperial Japanese Army.

In 1916, Ishii was admitted to the Medical Department of Kyoto Imperial University. In addition to learning both the best medical practices of the time and proper laboratory procedures, he also developed some strange habits.

He was known for keeping bacteria in petri dishes as “pets.” And he also had a reputation for sabotaging other students. Ishii would work in the lab at night after the other students had already cleaned up — and use their equipment. He would purposely leave the equipment dirty so the professors would discipline other students, which led them to resent Ishii.

But while the students knew what Ishii had done, he was apparently never punished for his actions. And if the professors somehow knew what he was doing, it almost seemed as if they were rewarding him for it.

It’s perhaps a sign of his growing ego that shortly after reading about biological weapons in 1927, he decided that he would become the best in the world at making them.

Shiro Ishii’s Immodest Proposal

Wikimedia Commons Special Naval landing forces of the Imperial Japanese Navy prepare to advance during the Battle of Shanghai in August 1937 — with gas masks firmly in place.

Shortly after reading the initial journal article that inspired him, Shiro Ishii began to push for a military arm in Japan that focused on biological weapons. He even directly pleaded with top commanders.

To truly grasp the scale of his confidence, consider this: Not only was he a lower-ranking officer suggesting military strategy, but he was also proposing the direct violation of relatively new international laws of war.

At the crux of Ishii’s argument was the fact that Japan had signed the Geneva agreements, but had not ratified them. Since Japan’s stance on the Geneva agreements was technically still in limbo, there was perhaps some wiggle room that would allow for them to develop bioweapons.

But whether Ishii’s commanders lacked his vision or nebulous grasp of ethics, they were skeptical of his proposal at first. Never one to take no for an answer, Ishii asked for — and ultimately received — permission to take a two-year research tour of the world to see what other countries were doing in terms of biological warfare in 1928.

Whether this signaled legitimate interest on the part of the Japanese military or simply an effort to keep Ishii happy is unclear. But either way, after his visits to various facilities across Europe and the United States, Ishii returned to Japan with his findings and a revised plan.

A Receptive Audience

Wikimedia Commons The Japanese soldiers bombed Chongqing, China from 1938 to 1943.

Despite the Geneva Protocol, other countries were still researching biological warfare. But, out of either ethical concerns or fear of discovery, no one had yet made it a priority.

So in the years preceding World War II, Japanese troops began to seriously consider investing their resources in this controversial weaponry — with the goal that their battle techniques would surpass all other countries on Earth.

By the time Ishii returned to Japan in 1930, a few things had changed. Not only was his country on track to wage war against China, nationalism as a whole in Japan burned a little brighter. The old country slogan of “a wealthy country, a strong army” was echoing louder than it had in decades.

Ishii’s reputation had also grown. He was appointed professor of immunology at the Tokyo Army Medical School and given the rank of major. He also found a powerful supporter in Colonel Chikahiko Koizumi, who was then a scientist at the Tokyo Army Medical College.

Wikimedia Commons Japanese army surgeon Chikahiko Koizumi. After World War II, he came under suspicion for being a war criminal, but he committed suicide before he could be properly investigated.

A veteran of World War I, Koizumi oversaw research into chemical warfare beginning in 1918. But around this time, he almost died in a lab accident after being exposed to a chlorine gas cloud without a gas mask. After his full recovery, he continued his research — but his superiors placed a low priority on his work at the time.

So it’s no surprise that Koizumi saw himself reflected in Shiro Ishii. At the very least, Koizumi saw someone similar enough to him who shared his vision for Japan. As Koizumi’s star continued to rise — first to Dean of the Tokyo Army Medical College, then to Army Surgeon General, then to Japan’s Minister of Health — he made sure that Ishii moved up along with him.

For Ishii’s part, he certainly enjoyed the praise and promotions, but nothing seems to have been more important to him than his own self-aggrandizement.

Ishii’s public work consisted of researching microbiology, pathology, and vaccine research. But as all those in the know understood, this was only a small part of his actual mission.

Unlike his student years, Ishii was rather popular as a professor. The same personal charisma and magnetism that had won over his teachers and commanders also worked on his students. Ishii often spent his nights out drinking and visiting geisha houses. But even while inebriated, Ishii was more likely to go back to his studies than to go to bed.

This behavior is telling on two counts: It shows the kind of obsessive man Ishii was, and it explains how he was able to persuade others to help him with his deranged experiments after he began working in China.

A Secret, Sinister Facility

Xinhua via Getty Images Unit 731 personnel conduct a bacteriological trial upon a test subject in Nongan County of northeast China’s Jilin Province. November 1940.

Following the invasion of Manchuria in 1931 and the establishment of the puppet client state Manchukuo shortly thereafter, Japan utilized the region’s resources to fuel its industrialization efforts.

Like the attitudes of Americans during the “Manifest Destiny” period of expansion, many Japanese soldiers saw the people living in the area as obstacles. But to Shiro Ishii, these residents were all potential test subjects.

According to Ishii’s theories, his biological research would require different types of facilities . For instance, he established a biological weapons facility in Harbin, China, but quickly realized that he wouldn’t be able to freely conduct involuntary human research in that city.

So he simply began to put together another secret facility that was about 100 kilometers south of Harbin. The 300-home village of Beiyinhe was razed to the ground to make way for the site, and local Chinese laborers were drafted to construct the buildings.

Here, Shiro Ishii developed some of his barbaric techniques, foreshadowing what would come in the notorious Unit 731.

Wikimedia Commons Unit 731’s Harbin facility was built on Manchurian land conquered by Japan.

The sparse records from the Beiyinhe facility offer a sketch of Ishii’s work there. With up to 1,000 prisoners crammed into the facility, the test subjects were a mixed group of underground anti-Japanese workers, guerrilla bands who harassed the Japanese, and innocent people who unfortunately got caught in a roundup of “suspicious persons.”

A common early experiment was drawing blood from prisoners every three to five days until they were too weak to go on, and then killing them with poison when they were no longer considered valuable to research. Most of these subjects were killed within a month after their arrival, but the number of total victims in the facility remains unknown.

In 1934, a prisoner rebellion broke out as the soldiers celebrated the Mid-Autumn Festival. Taking advantage of the guards’ drunkenness and the relatively lax security, some 16 prisoners were able to successfully escape. This is the main reason why we know what we do about that facility.

Despite the extreme risk to the security and secrecy of the operation, it’s possible that experiments continued at that site as late as 1936, before it was officially shut down in 1937.

Ishii, for his part, did not seem to mind the closure. He was already getting started with another facility — which was far more sinister.

The Josef Mengele Of Japan

Xinhua via Getty Images Unit 731 researchers conduct bacteriological experiments on captive child subjects in Nongan County of northeast China’s Jilin Province. November 1940.

Shiro Ishii is often compared to Josef Mengele, the German doctor known as the “Angel of Death,” who conducted sinister experiments in Nazi-occupied Poland.

The infamous Auschwitz-Birkenau concentration camp was a complex that killed its prisoners as part of its design. While many victims were executed in gas chambers, others were reserved for Mengele and his twisted medical experiments.

As an SS officer and member of the Nazi elite, Mengele had the authority to determine the fitness of prisoners, recruit imprisoned medical professionals as assistants, and force inmates into becoming his test subjects.

But unlike Ishii, Mengele was more limited in his power over the camp and in the effectiveness of his research. Auschwitz had been built to produce rubber and oil, and Mengele used the environment to conduct pseudoscience. His work fell under the guise of genetics , but it was often little more than pointless and cruel acts of sadism.

In many ways, Ishii had more control over his human subjects. His research was also more scientific — and monstrous. Just about all the horrors that occurred in the facilities had been thought up by Ishii — with the intention of turning human beings into data.

Expanding and building upon his earlier efforts, Ishii designed Unit 731 to be a self-sufficient facility, with a prison for his human subjects, an arsenal for making germ bombs, an airfield with its own air force, and a crematorium to dispose of human remains.

In another part of the facility were the dormitories for Japanese residents, which included a bar, library, athletic fields, and even a brothel.

But nothing at the complex could compare to Ishii’s house in Harbin, where he lived with his wife and children. A mansion left over from the period of Russian control over Manchuria, it was a grand structure that was remembered fondly by Ishii’s daughter Harumi. She even likened it to the home in the classic film Gone With The Wind .

Shiro Ishii And The Experiments At Unit 731

Xinhua via Getty Images The frostbitten hands of a Chinese person who was taken outside in winter by Unit 731 personnel for an experiment on how to best treat frostbite. Date unspecified.

If you know the name Unit 731, then you probably have some idea of the horrors that unfolded at Ishii’s facility — believed to be set up around 1935 in Pingfang. Despite decades of cover-up, stories of the cruel experiments that took place there have spread like wildfire in the age of the internet.

However, for all the discussion of freezing limbs, vivisections, and high-pressure chambers, the horror that tends be ignored is Ishii’s inhumane reasoning behind these tests.

As an army doctor, one of Ishii’s primary goals was the development of battlefield treatment techniques that he could use on Japanese troops — after learning just how much the human body could handle. For example, in the bleeding experiments, he learned how much blood the average person could lose without dying.

But at Unit 731, these experiments kicked into high gear. Some experiments involved simulating real-world conditions.

For example, some prisoners were placed in pressure chambers until their eyes popped out so that they could demonstrate how much pressure the human body could withstand. And some prisoners were injected with seawater to see if it could work as a replacement for a saline solution.

The most horrifying example touted around the internet – the frostbite experiment — was actually pioneered by Yoshimura Hisato, a physiologist assigned to Unit 731. But even this test had a practical battlefield application.

Unit 731 researchers were able to prove that the best treatment for frostbite was not rubbing the limb — the traditional method up until that point — but instead immersion in water a bit warmer than 100 degrees Fahrenheit (but never hotter than 122 degrees Fahrenheit). But the way they came to this conclusion was horrific.

Unit 731 researchers would lead prisoners outside in freezing weather and leave them with exposed arms that were periodically drenched with water — until a guard decided that frostbite had set in.

Testimony from a Japanese officer revealed that this was determined after the “frozen arms, when struck with a short stick, emitted a sound resembling that which a board gives when it is struck.”

When the limb was struck , this sound would apparently let the researchers know that it was sufficiently frozen. The frostbite-affected limb was then amputated and taken to the lab for study. More often than not, the researchers would then move on to the prisoners’ other limbs.

When prisoners were reduced to heads and torsos, they were then handed over for plague and pathogen experiments. Brutal as it was, this process bore fruit for Japanese researchers. They developed an effective frostbite treatment several years ahead of other researchers.

As with Mengele, Ishii and the other Unit 731 doctors wanted a wide sample of subjects to study. According to official accounts, the youngest victim of a temperature-changing experiment was a three-month-old baby .

The Brutality Of Weapons Testing

Xinhua via Getty Images A Unit 731 doctor operates on a patient that is part of a bacteriological experiment. Date unspecified.

Weapons testing at Unit 731 took several distinct forms. As with medical research, there were “defensive” tests of new equipment, such as gas masks.

Researchers would force their prisoners to test out the effectiveness of certain gas masks in order to find the best kind among the pack. Although unconfirmed, it is believed that similar testing led to an early version of the bio-hazard protection suit.

In terms of offensive weapons tests, these tended to fall under two different categories. The first was the deliberate infection of prisoners to study disease effects and to select suitable candidates for weaponization.

In order to better understand the impacts of each disease, researchers did not provide prisoners with treatment and instead dissected or vivisected them so that they could study the impact of the diseases on the internal organs. Sometimes, they were still alive while they were being cut open.

In a 1995 interview, one anonymous former medical assistant in a Japanese Army unit in China revealed what it was like to cut open a 30-year-old man and dissect him alive — without any anesthetic.

“The fellow knew that it was over for him, and so he didn’t struggle when they led him into the room and tied him down,” he said. “But when I picked up the scalpel, that’s when he began screaming.”

He continued, “I cut him open from the chest to the stomach, and he screamed terribly, and his face was all twisted in agony. He made this unimaginable sound, he was screaming so horribly. But then finally he stopped. This was all in a day’s work for the surgeons, but it really left an impression on me because it was my first time.”

The second type of offensive weapons testing involved the actual field testing of various systems that dispersed diseases. These were used against prisoners within the camp — and against civilians outside of it.

Ishii was diverse in his exploration of disease dispersal methods. Inside the camp, prisoners infected with syphilis would be forced to have sex with other prisoners who weren’t infected. This would help Ishii observe the onset of the disease. Outside the camp, Ishii gave other prisoners dumplings that were injected with typhoid and then released them so they could spread the disease.

He also passed out chocolates filled with anthrax bacteria to local children. Since many of these people were starving, they often didn’t question why they were receiving this food and unfortunately assumed it was just an act of kindness.

Sometimes, Ishii’s men would use air raids to drop innocuous items like wheat and rice balls and strips of colored paper above nearby cities. It was later discovered that these items were infected with deadly diseases.

But as horrific as these attacks were , it was Ishii’s bombs that truly placed him at the top of all other biological weapons researchers.

A “Gift” To Mankind

Xinhua via Getty Images Japanese personnel in protective suits carry a stretcher through Yiwu, China during Unit 731’s germ warfare tests. June 1942.

Ishii’s plague bombs carried an unusual payload. Instead of the usual metal containers, they would use containers made of ceramic or clay so that they would be less explosive. That way, they would be able to properly release plague-infected fleas on countless people.

Unable to improve off of the traditional means of spreading the “Black Death,” Ishii decided to skip the rat middleman. When his bombs exploded, the surviving fleas would quickly escape, seeking out hosts to feed on and spread the disease.

And that’s exactly what happened in China during World War II. Japan dropped these bombs on both combatants and innocent civilians in multiple towns and villages.

But Ishii’s master plan, “Operation Cherry Blossoms at Night,” intended to use these weapons against the United States .

If this plan would’ve succeeded, about 20 of the 500 new troops who arrived in Harbin would’ve been taken toward southern California in a submarine. They would’ve then manned an onboard plane and flown it to San Diego. And plague bombs would’ve then been dropped there in September 1945.

Thousands of disease-riddled fleas would’ve been deployed, as the troops took their own lives by crashing somewhere onto American soil.

However, America’s atomic bombings happened before this plan came to fruition. And the war ended before the operation was even fully mapped out. But ironically enough, it was America’s interest in Ishii’s research that ultimately saved his life.

In August 1945, shortly after the atomic bombings of Hiroshima and Nagasaki, the order came to destroy all evidence of the activities at Unit 731. Shiro Ishii sent his family ahead by railroad, remaining behind until his infamous facilities were destroyed.

The exact number of people killed by Unit 731 and its related programs remains unknown, but estimates usually range from about 200,000 to 300,000 (including the biological warfare operations). As for deaths due to human experimentation, that estimate typically ranges around 3,000. By the end of the war, any remaining prisoners were speedily killed off.

Although Ishii was also ordered to destroy all documentation, he carried some of his lab notes out of the facility with him before going into hiding in Tokyo. Then, the American occupation authorities paid him a visit.

Throughout the war, vague reports from China about unusual outbreaks and “plague bombs” had not been taken very seriously until the Soviets took Manchuria from the Japanese. By that point, the Soviets knew enough to have a vested interest in finding and securing General Ishii to “interview” him about his infamous research.

For better or for worse, the Americans got to him first. According to Ishii’s daughter Harumi, the American officers used her as a transcriber as they interrogated her father about his work.

At first, he played coy, pretending not to know what they were talking about. But after he secured immunity, protection from the Soviets, and 250,000 yen as payment, he began to talk.

All told, he’d revealed 80 percent of his data to the United States by the time of his death. Apparently, he took the other 20 percent to his grave.

A Deal With The Devil

Wikimedia Commons Unit 731 bombs on display at a museum on the site of where the Harbin bioweapon facility used to be.

In order to protect Ishii and maintain a monopoly on his research, the United States kept its word. The crimes of Unit 731 and other similar organizations were suppressed, and at one point they were even labeled “Soviet Propaganda” by American authorities.

And yet, a “top secret” cable from Tokyo to Washington in 1947 revealed: “Experiments on humans were … described by three Japanese and confirmed tacitly by Ishii. Ishii states that if guaranteed immunity from ‘war crimes’ in documentary form for himself, superiors, and subordinates, he can describe program in detail.”

To put it plainly, American authorities were eager to learn the results of experiments that they weren’t willing to perform themselves. That’s why they granted him immunity.

Although some of the research from Ishii was valuable, American authorities didn’t learn nearly as much as they thought they would. And yet they kept their end of the bargain. Shiro Ishii lived out the rest of his days in peace until he died of throat cancer at the age of 67.

Years after the agreement, North Korea made a startling allegation that the United States had dropped plague bombs on them during the Korean War.

And so a group of scientists from France, Italy, Sweden, the Soviet Union, and Brazil — led by a British embryologist — toured the affected areas to collect samples and issue a verdict in the 1950s.

Wikimedia Commons A page from the International Scientific Commission for the Facts Concerning Bacterial Warfare in China and Korea. Allegations that America used biological warfare during the Korean War remain controversial to this day.

Their conclusion was that germ warfare had indeed been used as North Korea claimed. Officially, this is also “Soviet Propaganda,” according to the United States. Or is it?

With a clear answer still missing, we are left with uncomfortable questions. Consider the following: In 1951, a now-declassified document showed that the U.S. Joint Chiefs of Staff issued orders to begin “large scale field tests… to determine the effectiveness of specific BW [bacteriological warfare] agents under operational conditions.” And in 1954, Operation “Big Itch” dropped flea bombs at the Dugway Proving Ground in Utah.

With that in mind, what is more likely? Are these actions coincidental to the Chinese and Soviets using part of the truth that they knew in an attempt to embarrass the Americans? Or, did someone secretly give the order to bring Shiro Ishii and his men out of retirement?

In any case, one thing is clear. Shiro Ishii never faced justice and died a free man in 1959 — all thanks to the United States deal with the Devil.

After reading about Shiro Ishii, the unhinged mind behind Unit 731, learn the full story of Operation “Cherry Blossoms at Night.” For a glimpse of what the operation may have looked like, check out the mysterious “Battle of Los Angeles” that may have been started by a Japanese balloon bomb.

PO Box 24091 Brooklyn, NY 11202-4091

JAVASCRIPT IS DISABLED. Please enable JavaScript on your browser to best view this site.

Japan's Biological Warfare Project

Experiments.

• Harbin museum
• Yoshio Shinozuka
• Documentaries

Unit 731 and Unit 100 were the two biological warfare research centres set up in spite of the Geneva Protocol of 1925 banning biological and chemical warfare.

Led by Lieutenant-General Ishii Shiro, 3,000 Japanese researchers working at Unit 731’s headquarters in Harbin infected live human beings with diseases such as the plague and anthrax and then eviscerated them without anesthesia to see how the diseases infected human organs.

Because of the Unit’s secret nature, there is no complete list of the experiments that were undertaken by Unit 731.

Testimonies from participants shed some light about parts of the experiments. An anonymous medical assistant described in a 1995 New York Times interview his first vivisection:

“The fellow knew that it was over for him, and so he didn’t struggle when they led him into the room and tied him down. But when I picked up the scalpel, that’s when he began screaming. I cut him open from the chest to the stomach, and he screamed terribly, and his face was all twisted in agony. He made this unimaginable sound, he was screaming so horribly. But then finally he stopped. This was all in a day’s work for the surgeons, but it really left an impression on me because it was my first time.”

But the Unit was not only infamous for its vivisections. Some prisoners sent to Unit 731 were taken outside and tied to stakes. The Japanese would then test new biological weapons such as plague cultures or bombs filled with plague-infested fleas on them.

Other studies involved exposing human guinea pigs, called ‘logs’ by the Japanese scientists, to their limits. Humans were locked inside pressure chambers to test how much the body could take before their eyes popped out.

Some human test subjects were taken outside during the harsh winter until their limbs froze off for the doctors to experiment how best to treat frostbite.

Since the Japanese army used poison gas during the war, one of the Unit 731’s mission was to develop a more potent poison gas, thus prisoners were subjected to poisoning.

In 1984, a graduate student at Keio Medical University in Tokyo found records of human experiments in a bookstore. The pages described the effects of massive dosages of tetanus vaccine. There were tables describing the length of time it took victims to die and recorded the muscle spasms in their bodies.

At least 3,000 people, not just Chinese but also Russians, Mongolians and Koreans, died from the experiments performed by Unit 731 between 1939 and 1945. No prisoner came out alive of the Unit’s gates. During the war, the Japanese Imperial Army used biological weapons developed and manufactured by Unit 731’s laboratory in Harbin throughout China, killing or injuring an estimated 300,000 people.

Inside Unit 731 and Japan’s Human Experiments in WW2

From 1939 to 1945, the world witnessed the deadliest war in history, as over 30 countries wound together in acrimony, strife, and bloodshed, leading to a war that claimed the lives of more than 100 million people all over the world. History reveals that the war was replete with different subplots, each significantly ravaging our shared humanity.

But of all these battlefronts, the Pacific Theatre, hosting the most extended series of battles during WW2, stands tall as the epicenter of the action.

Historians recorded that Japan started the war when it launched an attack on Manchuria in 1931 and invaded China in 1937. This invasion was instantly followed by disturbances and upheavals that shook China’s very foundations, culminating in a civil war and famine that claimed the lives of over 63 million persons, lasting until China’s liberation in 1945.

Imperial Japan did unleash unspeakable terror on China during its occupation. Still, all these are nothing compared to the atrocities perpetrated in Unit 731 – the very center-point of Japanese biological warfare units that plunged the already genocidal war into newer depths of horror.

What started as a research and public health agency with a noble, innocent beginning descended into an abyss of terror when Unit 731 grew an assemblage for weaponized diseases that could have killed every living thing on earth multiple times over if deployed to its maximum strength.

This rather sordid shift in purpose was designed for the eternal suffering of captives as disease incubators and test subjects which very well served its purpose until 1945 when Unit 731 shut down operations.

But before then, Unit 731 had committed some of the most degrading and torturous human experiments in human history.

Frostbite Tests

Perhaps, assigning Yoshimura Hisato to Unit 731 marked the beginning of doomsday for the Chinese captives. Here was a physiologist with an uncanny obsession for hypothermia, whose curiosity had no limits and who had almost no regard for human life.

Attempting to improve on Maruta’s research on limb injuries, Hisato submerged the limbs of Chinese captives in water and ice and held them until the limb – arm or leg – had frozen with visible ice coatings on the skin. Eye witness accounts say the limbs sounded like wood when hit with a plank. But for Hisato, this was only the beginning. 

He attempted different methods to rewarm the frozen limbs as rapidly as possible. In some cases, he would douse the limb with hot water; other times, he would hold the limbs close to an open fire. And sometimes, he would leave the subject untreated overnight to examine how long it would take for the subject’s blood to break off the frost.

Maruta and the Throes of Vivisection

Established as a research unit, Unit 731 was preoccupied with investigating how disease and injury affect the fighting ability of armed forces. However, “Maruta,” an arm of the Unit, went rogue when it took up the research by a notch, breaking the defined bounds of medical ethics, though, at that point, it only observed injuries and disease courses on patients.

The project began with volunteers from the Army, but as the experiments scaled new highs and the supply of volunteers ran out, the Unit soon turned its attention to Chinese prisoners of war and captives. Consent became a thing of the past, and there was no limit to what researchers could do.

At this point, Unit 731 referred to their confined research subjects as “Murata” or “logs.” Needless to say, the study methods deployed for these experiments were highly dehumanizing.

Vivisection, one of the most common practices in those days, deserves special mention here. This was a process whereby human bodies were mutilated without anesthesia to conduct studies and experiments in living systems.

In those days, thousands of persons, primarily Chinese captives, elderly farmers, and children, who suffered diseases such as the plague and cholera, had their organs removed and examined.

This was mainly to study the possible effects of their various diseases before their body decomposes after death. In some instances, subjects had their limbs detached and reattached to another half of their body, while some had their limbs frozen, crushed, or cut off to study the spread of gangrene in the body.

When a subject’s body had exhausted its use, they would drive lethal injections into their body or shoot them even while some were buried alive. None of these Unit 731 subject captives survived this dehumanizing confinement, whether Chinese, Korean, Russian, or Mongolian.

Atrocious Weapons Tests

In every war, weapons superiority is a central talking point for superpowers. The Japanese knew this, only that they took it too seriously.

As the war raged, the effectiveness of weapons manufactured became a significant question and an area of interest to the Army. As part of efforts to determine the potency of their weapons, Unit 731 huddled captives together within a firing range.

It blasted shots at them from different ranges using Japanese weapons such as bolt-action rifles, Nambu 8mm, machine guns, grenades, and pistols. In assessing the varying levels of effectiveness, researchers compared wound patterns and depths of penetration to dying inmates and actual deaths.

Traditional weapons like knives, swords, and bayonets were equally studied, except in this case, the victims were usually bound. Unit 731 also tested flamethrowers on covered and open skin, while gas chambers were built at strategic unit facilities to expose test subjects to blister agents and nerve gas.

Victims were bound in one place as heavy objects dropped on them to study crush injuries, while test subjects were wound up and deprived of food and water to learn how long the average human can survive without water.

In most cases, these victims drank only seawater or were impaled with injections of mismatched animal or human blood to analyze the process of transfusion and clotting.

Prolonged exposure to x-ray sterilized and maimed thousands of research subjects while inflicting severe burns in cases where the emitting plates are miscalibrated or placed too close to the participants’ genitals, faces, or nipples.

Unit 731 also studied the effects of high G-forces on pilots and falling paratroopers. They loaded human beings into large centrifuges, spinning them at extremely high speeds until they lost consciousness or died, typically at 10 to 15 G’s. They found that young children were more tolerant of acceleration forces.

Syphilis Studies on War Captives

History has shown that venereal diseases have inflicted major disruptions on organized armies since ancient Egypt. In attempting to prevent similar occurrences, the Japanese military took an interest in studying the symptoms and treatments of syphilis.

For a start, doctors at Unit 731 infested test subjects with syphilis, withheld treatments, and observed the progress of the illness.

However, Salvarsan, a primitive chemotherapy agent and contemporary treatment in those days, was administered within a specified period to assess the side effects of the disease.

Male subject carriers of syphilis were asked to rape male and female captives to ensure the disease was effectively transmitted.

The infected prisoners were closely monitored to observe the onset and spread of the illness. Where the first exposure resulted in zero infection, more subjects were raped until the infection was established.

Rape and Systematic Pregnancy

You may consider the syphilis experiment far too outrageous, but it probably pales compared to the spate of rape and forced pregnancy that characterized Unit 731’s operations.

The most common instance includes female captives being raped and systematically impregnated so that trauma and weapon experiments could be carried out on them.

These women were advertently infected with life-threatening diseases, doomed to crush injuries, chemical weapons exposure, shrapnel injuries, and bullet wounds.

After this, Unit 731 doctors opened up the pregnant subjects and studied the effects of these injuries on the fetuses.

It appears the ultimate objective was to transpose the findings into contemporary medicine, but even if Unit 731 researchers had published these findings, the papers might not have survived the war.

Fleas and Plagues on Chinese Civilians

As time passed, it became clearer that Japan’s Unit 731 was driven by an ultimate mission to develop weapons of mass destruction by 1939, to ravage the Chinese people, and destroy Allied forces, if time permitted.

The Unit rounded up tens of thousands of captives caged across different facilities in Manchuria, which imperial forces had occupied for decades.

The Japanese infected these inmates with the most lethal virus and pathogens science has ever known. Prominent examples of such deadly pathogens include yersinia pestis, which causes the pneumonic and bubonic plague , and typhus, which the researchers systematically spread from one inmate to another to depopulate notable areas.

The doctors bred the most dangerous strains and monitored patients as they advanced through various stages, from symptoms to spread. When victims survived, they were shot, and the sickest were left to bleed on the mortuary table if they fell ill.

The doctors would take their blood would infect other captives, and the sickest from this group would be bled to transfect the deadliest strain to another group of prisoners.

Once, a member of Unit 731 pitched the idea that the sickest captives should be spread out on a slab with a line inserted into their carotid artery.

That’s not all – when the blood has been sucked out of their heart which would be too weak to pump more blood, a military officer will jump on the victim’s chest with his leather boots. The officer did this with so much force and vigor that it crushed the captive’s ribcage, and blood would spurt into a designated container.

One of the significant plagues bred by the Unit – plague bacillus – was built into a vastly lethal pathogen. The last set of subjects was exposed to an overwhelming huddle of fleas.

These fleas were packaged and sealed with clay bomb casings. On 4th October 1940, Japanese bombers released these casings, each containing 30,000 blood-sucking fleas that were initially exposed to the prisoners in a Chinese village called Quzhou.

According to eyewitnesses, the bombing was accompanied by fine crimson dust settling on different surfaces of the town and a succession of terrible flea bites that ravaged everyone present.

A series of eyewitness accounts agreed that at least 2,000 Chinese civilians died of the plagues foisted by these fleas, with 1,000 more deaths in a nearby village called Yiwu after sick railway staff carried the pathogen to this location. Unit 731 also employed anthrax to launch this attack, killing at least 6,000 people.

As the war tailed to an end, Japan tried to bomb America with the same fleas, but to no avail. But this was perhaps the beginning of the end for Unit 731 because by August 1945, Hiroshima and Nagasaki had been bombed, and the Soviet Army invaded Manchuria and annihilated the Japanese Army. The emperor then read his surrender memo over the radio and disbanded Unit 731.

The research records and reports were burnt, and all the data and information generated by the Unit in 13 years were equally destroyed.

Some researchers returned to everyday civilian life in Japan as if nothing had happened, with some venturing into academics and medicine.

Some quarters believe that vestiges of the experiment may have found their way into academia and may have played significant roles in building war and medical technologies today.

However, these ideas are mere conjectures that thrive on the possibility that bits of information from inside Unit 731 may have escaped the 1945 purge.

But here’s what we know for sure: World War 2 is such a deadly detour in human history, and at the very center of the Pacific Theatre in Manchuria, humanity was bent backward – a thousand times and over, and for 13 solid years.

Related Posts

The Lovers of Valdaro – A Double Burial From Neolithic Italy

Quiz: How well do you know US presidents?

Leave a comment cancel reply.

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

• Election 2024
• Entertainment
• Newsletters
• Photography
• AP Buyline Personal Finance
• AP Buyline Shopping
• Press Releases
• Israel-Hamas War
• Russia-Ukraine War
• Global elections
• Asia Pacific
• Latin America
• Middle East
• Delegate Tracker
• AP & Elections
• 2024 Paris Olympic Games
• Auto Racing
• Movie reviews
• Book reviews
• Financial Markets
• Business Highlights
• Financial wellness
• Artificial Intelligence
• Social Media

Seiichi Morimura, who exposed the atrocities committed by the Japanese army’s Unit 731, dies at 90

Japanese writer Seiichi Morimura delivers a speech in Tokyo in March 2010. Morimura, whose nonfiction trilogy “The Devil’s Gluttony” exposed human medical experiments conducted by a secret Japanese army unit during World War II, died Monday, July 24, 2023. He was 90. (Kyodo News via AP)

• Copy Link copied

TOKYO (AP) — Renowned Japanese mystery writer Seiichi Morimura, whose nonfiction trilogy “The Devil’s Gluttony” exposed human medical experiments conducted by a secret Japanese army unit during World War II, died Monday. He was 90.

His official website and publisher, Kadokawa, said Morimura died of pneumonia at a Tokyo hospital.

“Akuma no Hoshoku,” or “The Devil’s Gluttony,” which began as a newspaper series in 1981, became a bestseller and created a sensation across the country over atrocities committed by Japanese Imperial Army Unit 731 in China.

From its base in Japanese-controlled Harbin in China, Unit 731 and related units injected war prisoners with typhus, cholera and other diseases as research into germ warfare, according to historians and former unit members. Unit 731 is also believed to have performed vivisections and frozen prisoners to death in tests of endurance.

Morimura began contributing articles to magazines while working in hotels. He won the prestigious Edogawa Rampo Prize for his mystery fiction in 1969 and the Mystery Writers of Japan Award in 1973.

Born in 1933 in Saitama, just north of Tokyo, Morimura survived harsh U.S. bombings of the Tokyo region toward the end of World War II and developed pacifist principles. He wrote a book about his commitment to defending Japan’s postwar pacifist Constitution and opposing nuclear weapons. He joined protests against a 2015 reinterpretation of the constitution by then-Prime Minister Shinzo Abe allowing greater military activity.

His 1976 novel “Ningen no Shomei” (“Proof of the Man”), a mystery about a young Black man who is murdered, revealed the dark side of postwar Japan and was made into a movie.

Another popular novel, “Yasei no Shomei” (“Proof of the Wild”), published a year later depicts a conspiracy over genocide in a remote village.

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• Europe PMC Author Manuscripts

United States Responses to Japanese Wartime Inhuman Experimentation after World War II: National Security and Wartime Exigency

Howard brody.

Director, Institute for the Medical Humanities, University of Texas Medical Branch, Galveston, TX USA

Sarah E. Leonard

Institute for the Medical Humanities, University of Texas Medical Branch, Galveston, TX USA

Jing-Bao Nie

Bioethics Centre, Division of Health Science, University of Otago, New Zealand; (adjunct/visiting) Hunan Normal University and Peking University, China

Paul Weindling

Department of History, Philosophy and Religion, Oxford Brookes University, Oxford, UK

In 1945-46, representatives of the United States government made similar discoveries in both Germany and Japan, unearthing evidence of unethical experiments on human beings that could be viewed as war crimes. The outcomes in the two defeated nations, however, were strikingly different. In Germany, the U.S., influenced by the Canadian physician John Thompson, played a key role in bringing Nazi physicians to trial and publicizing their misdeeds. In Japan, the U.S. played an equally key role in concealing information about the biological warfare experiments and securing immunity from prosecution for the perpetrators. The greater force of appeals to national security and wartime exigency help to explain these different outcomes.

Introduction

In 1945-46, U.S. officials made similar discoveries in both Germany and Japan, unearthing evidence of unethical experiments on human beings that constituted war crimes. The outcomes in the two defeated nations, however, were strikingly different. In Germany, the U.S. played a key role in bringing Nazi physicians to trial and publicizing their misdeeds. In Japan, the U.S. played an equally key role in concealing biological warfare experiments and securing immunity for the perpetrators. How we are to understand these very different responses?

Sheldon Harris, in his authoritative history of the Japanese biological warfare program, argues that during November 1945-March 1948:

The questions of ethics and morality as they affected scientists in Japan and in the United States never once entered into a single discussion… In all the considerable documentation that has survived…, not one individual is chronicled as having said [biological warfare] human experiments were an abomination and that their perpetrators should be prosecuted. The only concern voiced was that of the possibility of exposure that would cause the United States some embarrassment should word of the bargain ever become public knowledge. 1 , p. 305

In alleging that “questions of ethics and morality” were never raised, Harris seems to mean that no questions were answered in ways he agreed with. Much as we sympathize with his moral outrage, his statement is uninformative about the actual reasoning that the U.S. scientists employed as justification.

It is informative to compare the American response in Japan with the work of one important figure in Germany, Canadian Air Force officer John W. Thompson. Thompson recognized the German experiments as war crimes that set a dangerous precedent for the scientific community, and was uniquely influential in persuading Allied authorities to act. 2

We first briefly summarize the experiments in the two countries, then describe Thompson’s activities in postwar Germany. We next recount the U.S. investigations of Japanese biological warfare experiments. We conclude by comparing the two Allied responses to medical war crimes and propose reasons for the difference.

German and Japanese Experiments

The scope and nature of these unethical experiments is well described elsewhere. 1 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 A database created by Paul Weindling’s group at Oxford Brookes University has identified approximately 25,000 victims of German experiments, with confirming documentation for around 10,000. 3 Only about five percent of experiments ended with the death of the subjects but many others caused severe mutilation. 3

While Japanese biological warfare experiments were conducted at several locations, the best known is Unit 731, located near Harbin in Japanese-occupied Manchuria and commanded by Shiro Ishii. Established in 1936, Unit 731 eventually comprised 3000 personnel, 150 buildings, and capacity for holding 600 prisoners at a time for experimental use. Thousands of human beings were experimented on and killed at Unit 731 alone. Additional thousands were killed in other branches of Japan’s extensive biological and chemical warfare program. It is unlikely that accurate totals will ever become available. 1 , pp. 86-87

The Unit 731 experiments involved infecting prisoners, primarily Chinese prisoners of war and civilians, deliberately with infectious agents, and exposing prisoners to bombs designed to penetrate the skin with infectious particles. There were no known survivors of these experiments; those who did not die from infection were killed to be studied at autopsy, and in the waning days of the war all remaining prisoners were killed to conceal evidence. Some experiments were also done to test human responses to freezing temperatures and other extreme conditions.

Japanese military units also carried out field testing of disease-spreading weapons against both enemy troops and civilian populations. Additional thousands of deaths were caused by spreading plague-infected fleas and cholera bacilli in China in this manner, even though the experimenters developed no really efficient and well-controlled method for dispersing such agents.

The Nazis justified their experiments on three grounds—racist, eugenics/public health, and wartime national interests. The victims (primarily Jews, Roma, and Soviet prisoners of war) were believed to be racially inferior to the German-Aryan stock. Nazi party propaganda, especially effective among physicians, described the threat posed to the German people ( volk ) by racial contamination and unbridled reproduction among those with “unfit” genes. With the start of war in 1939, the attitude had been created that it seemed indefensible that the flower of German youth were facing death on the battlefield unless these racially inferior beings were also sacrificed for the war effort. 4

Two of these justifications motivated the Japanese. They viewed the Chinese and Koreans as racially inferior. 10 They also appealed frequently to patriotism. 11 They were not, however, concerned about threats to Japanese racial purity; rather they simply wished to eliminate inferior populations and occupy their territories for Japanese imperialist expansion. The Japanese also argued that the prisoners used as experimental subjects, as suspected resisters and communists, would have been executed in any event.

The Role of John W. Thompson

A person whose important role in post-war events has not been sufficiently recognized is John W. Thompson. Born in Mexico of American parents, educated in the U.S., and a medical graduate of Edinburgh, John West Thompson (1906-1965) entered World War II as an officer in the Royal Canadian Air Force (RCAF). 2 Thompson possessed varied expertise. He was a skilled enough psychiatrist to assess German war crimes defendants for underlying psychopathology. He was prominent enough in medical research later to be offered (and decline) the physiology chair at the University of Ottawa in 1946. He had studied high-altitude flying, fitting him to evaluate German wartime research in that area. Finally, he had worked at Harvard during the 1930s with physiologists Andrew Ivy and Leo Alexander, who became central figures in the Nuremberg Doctors’ Trial. 12 , 13

When he arrived in Germany in May, 1945, Thompson’s first experience involved the care of the survivors of the Bergen-Belsen concentration camp. Even after liberation, deaths mounted alarmingly from malnutrition, a typhus epidemic, and inadequate medical response.

Thompson was then assigned the task of assessing the results of German aeronautical-stress research. He quickly discerned that much of this research was conducted in an unethical manner, as was confirmed by interviews with both German scientists and surviving subjects. Eventually Thompson was named Secretary-General of the International Scientific Commission (War Crimes). However, Thompson’s influence was exercised largely through personal contacts and diplomacy. Weindling believes that his behind-the-scenes role was important enough to merit the title “godfather of both the Nuremberg Code and informed consent.” 2 , p. 148

In November 1946, Thompson outlined his plans for the International Scientific Commission in a report to Lester Pearson, then Canada’s Under Secretary of State for External Affairs:

…[T]o gather all evidence of German experimental work carried out in an unethical manner on human beings, and as representative scientific bodies, to pass judgment on the value of the scientific results obtained condemn, in the name of science, the prosecution of such experiments, and finally, lay down some definition of what may be termed a justifiable experiment where a human being is used as a subject. 2 , p.125

These priorities reflect several ethical judgments. First, while the medical superintendent of the United Nations Relief and Rehabilitation Administration, T.B. Layton, had argued that all Nazi medical research data should be destroyed, 2 , p. 93 , Thompson thought that science demanded that any valuable results be preserved. At the same time he viewed the means of obtaining those data as unethical and criminal. Indeed, Thompson appears responsible for introducing the idea of a “medical war crime” into the official thinking of the Allied occupation in November 1945. Finally, when many thought the Nazis uniquely depraved, Thompson worried that scientists in other nations were equally capable of conducting unethical human experiments unless clear ethical boundaries were erected.

Thompson’s scientific intelligence team preserved and microfilmed a treasure trove of captured German research records—files later used by the Nuremberg prosecutors at the Doctors’ Trial. They also interviewed many Nazi scientists, but never discussed trading immunity from prosecution for access to scientific information. Among the many examples of the influence Thompson exerted over the U.S.-led responses through his personal diplomacy was helping to assure that the scientific intelligence work was closely coordinated with war crimes investigation units.

Japan: Scientific Investigations

The Japanese scientists were more astute than the Germans, both in banding together to plan their response to the American investigations and in realizing that the American interest in their data gave them a powerful bargaining chip. Like Scheherazade in the Arabian Nights tales, the Japanese interrogees became adept at revealing just enough in each interview, leaving what was yet unsaid as a tantalizing demonstration of how valuable their continued freedom would be to U.S. interests. 1 , p. 265

Lt. Col. Murray Sanders, a bacteriologist was the first investigator from the U.S. biological warfare unit at Camp Detrick, Maryland to travel to Japan. Sanders was told by several interviewees in September and October 1945 that the Japanese military had engaged solely in defensive research, as biological warfare was “clearly against humanity.” 14 The repetition of this phrase suggested a prearranged script. Sanders trusted his translator, Lt. Col. Ryoichi Naito, not realizing that Naito had served in Unit 731 and was deliberately manipulating the interrogations. In a 1983 interview, Sanders admitted that he had been “deceived” during his nine-week investigation 1 , p.182

The second American investigator, Lt. Col. Arvo T. Thompson, was similarly unable to extract correct information, but left in May 1946 increasingly convinced that the truth was being withheld. Gen. Ishii told Thompson that biological warfare was “inhumane” and would (if the Japanese had conducted such research) “defile the virtue and benevolence of the Emperor.” 15 This was a clear statement from a Japanese source, however cynically provided, that biological warfare experiments were unethical.

The third American scientist-investigator, Dr. Norbert H. Fell, a civilian employee of Camp Detrick, arrived in 1947. Fell was more knowledgeable than his two predecessors, whose reports had primed him to look out for deception. After testing Fell, Ishii’s group apparently decided to reveal that human experiments had, in fact, been conducted for biological weapons development. Their selected go-between was a “prominent businessman,” Kanichiro Kamei, whom Fell interviewed on April 21-22, 1947. Kamei was a PhD from Columbia University who had earlier served as a translator during the investigation conducted by Murray Sanders, said that despite his efforts to “persuade the Japanese to reveal everything,” 16 “the interrogations…were too soon after the surrender. However, if the men who actually know the detailed results of the experiments can be convinced that your investigation is from a purely scientific standpoint, I believe that you can get more information. … I believe it will reassure any personnel…that you are not investigating ‘war crimes.’” Referring to a Japanese officer being interrogated, Kamei told Fell, “MASUDA admitted to me that experiments were carried out on humans…. The personnel involved in carrying out these human experiments took a vow never to disclose information. However, I feel sure that if you handle the investigation from a scientific point of view, you can obtain detailed information.” 17

Two days later, Kamei stated that the Japanese feared that information given to the US “will be discovered by Communists and passed to Russia.” Those behind Kamei now saw that an emerging U.S. priority was keeping biological warfare information out of Communist hands. Kamei told Fell, “The human experiments were extensive enough to reach scientific conclusions. …conclusions [that] are in no way based on imagination.” 18 Having previously lied that all documents had been destroyed and that the surviving officers of Unit 731 had only hazy recollections of experiments, the Japanese now changed course and reassured the Americans that they had valuable information to trade for immunity from prosecution.

Fell, therefore, became the first American scientist made directly aware of activities that clearly constituted war crimes (assuming that the human experiments had been carried out without any semblance of voluntary consent). His response was to adopt Kamei’s proposal, that almost certainly originated with Ishii. Fell proceeded to inform each interrogated subject, “Investigation was to obtain scientific and technical data and was not concerned with ‘war crimes.’” 1 , p. 275, 19 Harris is unsure who authorized Fell to offer such assurances; Fell lacked the military authority to make such a move on his own. 1 , p. 278

However, in an addendum to his final report, dated June 24, 1947, Fell noted that the “information that has been received so far is proving of great interest here and it certainly will have a great deal of value.” 20 He then added:

At a conference yesterday at which the Chief of the Chemical Corps and representatives of the War, State and Justice Departments were present, it was informally agreed that the recommendations of the C.inC., FEC [Commander-in-Chief, Far East Command, i.e. General Douglas MacArthur], and the Chief, Chemical Corps would be accepted, i.e. that all information obtained in this investigation would be held in intelligence channels and not used for ‘War Crimes’ programs. 17

Harris argues that the Joint Chiefs of Staff would have had to approve a decision of this gravity, 1 , p. 278 and they in turn would have proceeded only with cabinet-level if not Presidential approval. 1 , p. 279 This decision kept all information about the human biological warfare experiments within intelligence channels, labeled top secret, whereas war crimes prosecution would entail public disclosure. The Fell report shows that these options were weighed and that scientific and military value took priority over ethical and criminal accountability.

The final report by U.S. scientists from Camp Detrick was submitted in December 1947, by technical director Dr. Edwin V. Hill and staff pathologist Dr. Joseph Victor. Ishii’s group now gave the Americans detailed reports on the experimental program, including a listing of 8000 pathological slides and hundreds of color drawings.

From an ethical standpoint, the Hill-Victor report is most notable for statements that have since been widely quoted. 21 Hill and Victor summarized the Japanese data, “Such information could not be obtained in our own laboratories because of scruples attached to human experimentation….It is hoped that the individuals who voluntarily contributed this information will be spared embarrassment because of it and that every effort will be taken to prevent this information from falling into other hands.” 22 The ethical reasoning implicit in this passage seemed to be:

• U.S. scientists have “scruples” regarding experimentation on humans. The Japanese scientists had no such scruples, indicating that their activities were unethical if not criminal.
• Having conducted unethical and criminal experiments, the Japanese scientists are therefore in a position to be embarrassed by their revelation.
• Saving the Japanese scientists (who belatedly cooperated with the U.S. inquiry) from embarrassment is a higher ethical priority than securing accountability for war crimes.
• The overriding goals are first, to secure these unique (because unscrupulous) data for the U.S., and second, to prevent them from “falling into other [i.e., Communist] hands.”

Hill and Victor added a further argument based on cost-effectiveness. They calculated that the U.S. had so far spent approximately 250,000 yen in its investigations of the Japanese biological warfare program. By contrast, Ishii’s research had cost “many millions of dollars and years of work” (with no mention of the human costs in lives and misery). In short, the U.S. had paid proportionally a “mere pittance” compared to the cost of generating these data. 19 This became a further argument for taking the data and assuring that the Japanese who provided it were not subjected to “embarrassment.”

Although conjecture, it is tempting to read into these statements a further conclusion that the Americans, contrasting their slow progress at Camp Detrick with the apparently vast accomplishments of Unit 731, were appreciative of what the Japanese lack of “scruples” had achieved.

Military Legal Investigations

The Japanese scientists were worried about war crimes prosecutions then being pursued by the Adjutant General’s Office. 1 , p. 288 The difference between the scientific and legal investigations formed a striking contrast between Germany and Japan. In Germany, the very idea of “medical war crimes” originated among the scientists investigating the experiments, who then lobbied the legal staff to pursue prosecutions. In Japan, the legal staff was independently seeking evidence to prosecute war crimes, and the scientists were instrumental in stopping them.

The legal section received both anonymous and signed accusations against Ishii. In November, 1946, investigators wrote, “This information is being included in this report as another indication of mounting complaints concerning the alleged activities of General ISHII and his associates…principal among which are alleged to have been infecting Prisoners of War with glanders for experimental purposes.” 23

However, further investigation and prosecution was stymied by the Joint Chiefs of Staff as early as March 1947. They ordered the Adjutant General’s Office to seek the approval of military intelligence (G-2) for any further activities and to treat all related documents as top secret. It took another year for the final decision to be reached at the highest levels. The complicating factor was repeated requests from the Soviets, officially U.S. allies against Japan, to be allowed to interrogate the Japanese scientists. U.S. authorities were torn between the desire to deny the Russians access, even at the cost of an international incident, and their suspicion that allowing the Soviets to interrogate the Japanese with Americans present could reveal useful tips about the Soviets’ current knowledge of bacteriological warfare. 1 , pp. 291-300

A task force of the State-War-Navy Coordinating Committee (SWNCC), a high-level group overseeing the military occupation, indirectly admitted on August 1, 1947 their shaky ethical position. They acknowledged that Unit 731 “violate[d] the rules of land warfare,” 24 and that the Japanese experiments were similar to those for which Germans had been tried for war crimes. 1 , p. 301, 25

The task force now needed justification for refusing to prosecute. First they concluded that the evidence available was insufficient to document legal guilt. This was fallacious, both because it misrepresented the evidence then documented in Adjutant General reports, and also ignored the fact that confirmatory evidence was not being pursued specifically in response to military orders. Finally, the task force appealed to the same reasoning in the scientific reports: “The value to the U.S. of Japanese [biological warfare] data is of such importance to national security as to far outweigh the value accruing from ‘war crimes’ prosecution.” 1 , p. 301, 26 This conclusion amounted to a major coup for Ishii. When the full assessment of the Japanese data was finally completed, the Camp Detrick staff learned virtually nothing beyond what the Americans had already discovered by more “scrupulous” means. 1 , pp. 301-302

The SWNCC did not act on the task force’s recommendations for another six months. The Joint Chiefs’ final order placing all information under G-2 purview and ceasing all prosecutions against Ishii and associates was sent on March 13, 1948. By that time the Toyko war crimes trials against high Japanese military officials had been concluded, so the SWNCC review constituted a delaying tactic. 1 , p. 304

The aftermath to the cover-up of Japanese medical war crimes has been extensively documented elsewhere. 1 , 9 , 10 , 27 Unlike the U.S., the Soviet Union tried twelve captured Japanese military personnel from Unit 731 in Khabarovsk for war crimes and later published the proceedings. 1 , 10 , 28 U.S. authorities dismissed the proceedings as communist propaganda, though in hindsight the information presented was reasonably accurate. 10 , 29 The relatively light sentences given to the perpetrators, compared to the seriousness of the charges against them, suggested that the Soviets, like the Americans, traded leniency for access to data. 1 , 10

Discussion: Wartime Exigency

The Allies’ ethical decisions differed sharply in Germany and in Japan. The divergence can be explained partly by Japanese ruthlessness. Thompson was probably influenced by his direct contact with survivors of the concentration camps. The Japanese assured that no Allied personnel could encounter survivors of Unit 731, because they left no survivors. The women of Ravensbrück, who displayed their experimental wound scars, were among the most effective prosecution witnesses at Nuremberg; 7 the Japanese eliminated all potential witnesses.

Contrary to Harris’s claim that no ethical thinking appears in the American documents on Japan, there was no lack of ethical perception. 30 The Americans clearly saw a problem requiring ethical justification. Although today we regard their ethical thinking as seriously flawed; nevertheless, it was a form of ethical reasoning.

Previous analyses of the Nazi and Japanese transgressions and the U.S. cover-up have stressed national security concerns and nationalist ideology. 27 , 29 , 31 We suggest expanding this list to include wartime exigency .

National security, by itself, explains why basic human rights might be overridden by measures presumed necessary for national survival. This explanation, however, cannot fully account for the reasoning we encounter in post-war occupied Japan. Wartime exigency better captures the sense of urgency and the impatience with a full discussion of ethical options or with a fastidious inquiry into abuses of rights. National security may ultimately set the actors’ priorities, but cannot by itself explain the way decisions are made or not made. By contrast, “Don’t you realize that there’s a war going on?” better accounts for the reasoning recorded in the American documents. As Edmund Pellegrino summarized the rationalizations of the Nazi physicians, “To resist would have been treasonous; ethics must be subordinate to the demands of war.” 32 , p. 308

In its moral implications, wartime exigency might be seen as a darker version of carnival (when “carnival” is viewed as a general cultural phenomenon rather than as any specific, local celebration). 33 , 34 All year, people chafe under social constraints, which especially affect the underclasses. Once a year, people are able to break these constraints by overturning the usual social conventions, wearing masks to escape personal responsibility. Since even the underclasses have a stake in maintaining the social order, all are reassured that this overturning of convention is only temporary, and in a few days things will return to normal.

In peacetime, people who have strong cruel, sadistic impulses chafe at the moral constraints that forbid them from acting upon these impulses. People who have such impulses are often poorly equipped to engage in careful moral reasoning, so they may also be frustrated when, better fitted for casuistical reasoning, appear to get away with shady moral behavior. Wartime loosens unwelcome constraint for such individuals. They act out their impulses, citing the highest of motives -- patriotism. They feel free to thwart anyone who questions their morality, since “Don’t you know there’s a war going on?” cuts off all moral debate at the outset. Finally, should any guilt feelings arise, they can comfort themselves with the illusion that all this is only temporary--soon the war will be won, peace will ensue, and the normal moral order can be restored.

In another example of wartime exigency trumping human rights, David Rothman describes the Committee on Medical Research (CMR) that oversaw war-related science in the U.S. during 1941-45. The CMR accepted that research on human subjects required informed, voluntary consent. However, they applied that understanding inconsistently. They approved, for example, a study of an anti-malarial drug in 500 Illinois prisoners who were deliberately infected with the disease; one prisoner died. They proudly reported these experiments in press releases that lauded the inmates’ willingness to volunteer, stating, “these one-time enemies to society appreciate to the fullest extent just how completely this is everybody’s war.” 35 Any concerns about the prisoners’ ability to consent voluntarily to risky experiments were eclipsed by war-effort fervor.

Wartime exigency does more than simply prioritize national security over human rights. It urges toughness and decisiveness in decision-making, so that a moral blindness that would be seen as a deficiency in other times is instead seen as a virtue and a necessity.

Wartime exigency is worth labeling as a specific factor alongside national security particularly because of how our contemporary culture is seemingly engaged in a perpetual state of war. The war against the Axis powers was immediately supplanted by the Cold War, and the exigencies of that war were viewed as justifying the egregious actions taken in Japan. American society saw the end of the Cold War in 1989, but then declared an interminable War on Terror in 2001, and that most recent war has been implicated in a number of indefensible ethical and policy choices. 36

Conclusions

Thompson in Germany decided that the war was over, that the Germans had done terrible things under the pressure of racism, national security, and wartime exigency, and that future scientists in other nations would be tempted to commit similar crimes unless people decisively spoke out. The American scientists and policymakers in Japan decided that a new war was being waged and that national security and wartime exigency justified exonerating the perpetrators of Unit 731 and covering up their crimes.

By proposing wartime exigency as one ethical reason for the American cover-up, we do not mean to suggest that this reason operated without certain political and socio-cultural contexts, particularly the Cold War environment. 32 , 34 Another socio-historical element that has not been discussed, to our knowledge, is the role of racism. It might appear that racism played only a relatively minor part in American calculations. However, there was an obvious double standard in the American postwar responses to the experiments upon different nationalities. A U.S. tribunal in Yokohama in 1948 indicted nine Japanese physician-professors and medical students for conducting vivisection upon captured American fliers. 37 Two professors were sentenced to death and others to 15-20 years’ imprisonment, much harsher than the sentences of the Russian Khabarovsk trial. The war between Japan and the United States was not only a war of empires and powers, but also a war of races. 38 The military and political end of the Pacific war did not immediately end the racist socio-historical context.

One might object that our condemnation of events in Japan lacks ethical substance, since it might simply count as an argument of the form, “People did something years ago; today we would condemn what they did; therefore we must be right and they must be wrong.” We believe that we have defended against this objection by comparing two reactions to wartime experiments that were instituted by the same nation at roughly the same time. We have argued that the U.S. position in Japan would stand condemned as unethical if one merely applied the same standards that were then being applied in Germany.

Another objection might compare the tack taken by Americans in Japan with common law-enforcement practices, granting selective immunity to certain criminals as part of a wider effort to fight crime. There are several reasons why this analogy fails. First, if anyone were to adopt a strategy of granting immunity to gather confessions which would then lead to the prosecution of guiltier parties, it would have been the military legal authorities. But we have seen that it was the legal authorities who were seeking war crimes prosecution, while the scientific authorities were all for granting immunity. Second, and more telling, there was no effort to use any of these confessions as tools to prosecute other guilty parties. The overall goal of the U.S. effort in Japan was effectively to grant immunity to the entire Japanese medical profession, and to assure that no prosecution for “medical war crimes” ever took place. Far from being an acceptable strategy in a difficult situation, the U.S. cover-up met both ethical and legal criteria for “complicity after fact.” 27

According to the arguments we have put forth, it is essential to condemn both the Japanese war criminals and the Americans who covered up their crimes. But mere condemnation risks treating the Japanese perpetrators and the American officials as the radical “others” of humanity, our moral inferiors. To pursue a deeper understanding is not to rationalize or justify the atrocities but to identify the historical and ethical causes of why things went so terribly wrong. However faulty the ethical reasoning employed in the cover-up, by studying it we gain important insights into where such flawed reasoning may next be applied today and tomorrow.

Acknowledgments

We are grateful to Dr. Sheldon Rubenfeld and the Center for Medicine after the Holocaust for arranging the tour during which HB met PW and became aware of the importance of John Thompson in post-war events. PW acknowledges Wellcome Trust Grant No 096580/Z/11/A on research subject narratives and AHRC Grant AH/E509398/1 on Human Experiments under National Socialism. Griffin Trotter provided valuable comments in review of the manuscript.

Contributor Information

Howard Brody, Director, Institute for the Medical Humanities, University of Texas Medical Branch, Galveston, TX USA.

Sarah E. Leonard, Institute for the Medical Humanities, University of Texas Medical Branch, Galveston, TX USA.

Jing-Bao Nie, Bioethics Centre, Division of Health Science, University of Otago, New Zealand; (adjunct/visiting) Hunan Normal University and Peking University, China.

Paul Weindling, Department of History, Philosophy and Religion, Oxford Brookes University, Oxford, UK.

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings
• My Bibliography
• Collections
• Citation manager

Save citation to file

Email citation, add to collections.

• Create a new collection
• Add to an existing collection

Add to My Bibliography

Your saved search, create a file for external citation management software, your rss feed.

• Search in PubMed
• Search in NLM Catalog
• Add to Search

U.S. Complicity and Japan's Wartime Medical Atrocities: Time for a Response

Affiliation.

• 1 a Ghent University.
• PMID: 26030498
• DOI: 10.1080/15265161.2015.1028659

Shortly before and during the Second World War, Japanese doctors and medical researchers conducted large-scale human experiments in occupied China that were at least as gruesome as those conducted by Nazi doctors. Japan never officially acknowledged the occurrence of the experiments, never tried any of the perpetrators, and never provided compensation to the victims or issued an apology. Building on work by Jing-Bao Nie, this article argues that the U.S. government is heavily complicit in this grave injustice, and should respond in an appropriate way in order to reduce this complicity, as well as to avoid complicity in future unethical medical experiments. It also calls on other U.S. institutions, in particular the Presidential Commission for the Study of Bioethical Issues, to urge the government to respond, or to at least inform the public and initiate a debate about this dark page of American and Japanese history.

Keywords: Unit 731; accessory after the fact; apology; complicity; human experimentation; medical ethics guidelines; medical war crimes.

PubMed Disclaimer

• The U.S. Complicity in Japan's Medical War Crimes: A Restatement on Why the U.S. Government Should Apologize and the U.S. Community of Bioethics Should Respond. Nie JB. Nie JB. Am J Bioeth. 2015;15(6):50-2. doi: 10.1080/15265161.2015.1028672. Am J Bioeth. 2015. PMID: 26030499 No abstract available.
• The diptych: Nazi and Japanese bioscience war crimes. Miles SH. Miles SH. Am J Bioeth. 2015;15(6):52-4. doi: 10.1080/15265161.2015.1028667. Am J Bioeth. 2015. PMID: 26030500 No abstract available.
• U.S. Complicity and Japan's Atrocities: How to Respond? Yudin B. Yudin B. Am J Bioeth. 2015;15(6):55-6. doi: 10.1080/15265161.2015.1028677. Am J Bioeth. 2015. PMID: 26030501 No abstract available.
• When saying sorry is not enough: acknowledging past wrongs in human subjects research. Aultman J. Aultman J. Am J Bioeth. 2015;15(6):57-9. doi: 10.1080/15265161.2015.1028670. Am J Bioeth. 2015. PMID: 26030502 No abstract available.
• Looking to the Future From the Past: Take Home Lessons From Japanese World War II Medical Atrocities. Strous RD, Zivotofsky AZ. Strous RD, et al. Am J Bioeth. 2015;15(6):59-61. doi: 10.1080/15265161.2015.1028666. Am J Bioeth. 2015. PMID: 26030503 No abstract available.
• Rather than responding to the past, shape the future instead. Kaur S. Kaur S. Am J Bioeth. 2015;15(6):61-3. doi: 10.1080/15265161.2015.1028668. Am J Bioeth. 2015. PMID: 26030504 No abstract available.

Similar articles

• The United States cover-up of Japanese wartime medical atrocities: complicity committed in the national interest and two proposals for contemporary action. Nie JB. Nie JB. Am J Bioeth. 2006 May-Jun;6(3):W21-33. doi: 10.1080/15265160600686356. Am J Bioeth. 2006. PMID: 16754432
• The use of executed Nazi victims in anatomy: Findings from the Institute of Anatomy at Gießen University, pre- and post-1945. Oehler-Klein S, Preuss D, Roelcke V. Oehler-Klein S, et al. Ann Anat. 2012 Jun;194(3):293-7. doi: 10.1016/j.aanat.2012.02.011. Epub 2012 Mar 16. Ann Anat. 2012. PMID: 22483508 Review.
• Beyond consent: the potential for atrocity. Gaw A. Gaw A. J R Soc Med. 2006 Apr;99(4):175-7. doi: 10.1177/014107680609900413. J R Soc Med. 2006. PMID: 16574967 Free PMC article. Review. No abstract available.
• Effects of age, period, and cohort on the prevalence of frailty in Chinese older adults from 2002 to 2014. Li S, Fan W, Zhu B, Ma C, Tan X, Gu Y. Li S, et al. Front Public Health. 2022 Aug 12;10:935163. doi: 10.3389/fpubh.2022.935163. eCollection 2022. Front Public Health. 2022. PMID: 36033734 Free PMC article.
• In the Shadow of Biological Warfare: Conspiracy Theories on the Origins of COVID-19 and Enhancing Global Governance of Biosafety as a Matter of Urgency. Nie JB. Nie JB. J Bioeth Inq. 2020 Dec;17(4):567-574. doi: 10.1007/s11673-020-10025-8. Epub 2020 Aug 25. J Bioeth Inq. 2020. PMID: 32840850 Free PMC article.
• The value of bioethical research: A qualitative literature analysis of researchers' statements. Mertz M, Fischer T, Salloch S. Mertz M, et al. PLoS One. 2019 Jul 29;14(7):e0220438. doi: 10.1371/journal.pone.0220438. eCollection 2019. PLoS One. 2019. PMID: 31356629 Free PMC article.

Publication types

• Search in MeSH

Related information

Linkout - more resources, full text sources.

• Taylor & Francis
• Citation Manager

NCBI Literature Resources

MeSH PMC Bookshelf Disclaimer

The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). Unauthorized use of these marks is strictly prohibited.

Inside Japan's Horrifying WWII Biological Warfare Project

While most people are aware of the human experimentation carried out by the Nazis in World War II, the human experimentation done by the Japanese is less notorious but just as horrifying. During World War II, the Imperial Japanese Army undertook a variety of experiments on people, with biological warfare at the forefront of their endeavor. Imprisoned people were electrocuted, shot, frozen, and even put into pressure chambers. In addition, the Japanese experimented with a variety of diseases, including anthrax and bubonic plague, in the hopes of creating a devastating biological bomb. 

One of the reasons why these atrocities are less well-known is because the United States government decided not to charge the Japanese doctors and researchers with war crimes in exchange for the information that they'd acquired. However, since the Soviet Union went ahead with trials and released all the testimonies, there are many firsthand accounts of what occurred. 

Over the years, Japan has slowly admitted to some of the atrocities that occurred in the various biological warfare units, but many Japanese textbooks fail to include details of Unit 731 . This is a look inside Japan's horrifying World War II biological warfare project.

What was Unit 731?

After the Japanese invaded the Chinese province of Manchuria in 1931, they quickly set up a puppet government, Manchukuo. According to The Harvard Gazette , while Manchukuo was advertised as a modern Pan-Asian state, the regime favored Japanese interests at its best and conducted horrifying human experimentation at its worst.

In addition to the experimentation in Manchukuo, the Japanese ran human experimentation units all over, such as Unit Ei 1644 in Nanjing and Unit 2646 in inner Mongolia. They spanned all the way to Singapore, as well, with Unit 9420 . Unit 731 was just one out of several, but it became infamous once the extent and variety of its atrocities became known to the public. Despite the fact that the Japanese tried to destroy all evidence of these units in the final days of World War II, the Soviet army found shallow graves with thousands of dead Chinese and Mongolian people as they moved into Manchuria.

Unit 731 began operating in 1937 in Harbin, undisturbed by the Manchukuo puppet government. According to the Atomic Heritage Foundation , Unit 731 was originally started to promote public health and soon turned toward research that would be beneficial to Japanese soldiers, such as testing the ways that the human body fights against disease and withstands thirst and hunger. But pretty soon, it would become the stage for some of the most heinous experiments of World War II . 

Who was Shirō Ishii?

Unit 731 was led by Shirō Ishii, a Japanese army medical doctor who'd been experimenting with the application of biological warfare. According to Factories of Death   by Sheldon H. Harris, Ishii wrote to his superiors in Tokyo in 1931 informing them that "due to [their] great help we have already achieved a great deal in our bacteria research" and requested a transfer to Manchukuo to start developing new weapons.

Ishii transferred to Harbin in 1932, according to PBS . In order to ensure secrecy, Ishii relocated his group outside of the city to Zhong Ma Camp in Beiyinhe. However, after the prison camp suffered a jailbreak and an explosion in 1935, thought by many to be sabotage, Ishii moved his facility to Pingfang, and in 1936, construction began for the camp that became known as Unit 731.

Ishii told his doctors that while the research done at Unit 731 might go against their principles, "I beseech you to pursue this research, based on the dual thrill of 1), a scientist to exert efforts to probing the truth in natural science and research into, and discovery of, the unknown world and 2) as a military person, to successfully build a powerful military weapon against the enemy." In the end, the United States granted Ishii immunity in exchange for details of his experimentation. He died a free man in Tokyo in 1959.

Transfusion experiments

Ever since William Havey discovered the circulation of blood in 1628, people around the world have experimented with blood transfusions. According to Popular Science , there was even a time in the late 1800s when doctors in North America were experimenting with milk transfusions as a blood substitute.

Unit 731 followed this eccentric tradition with grotesque experiments of their own. According to the Eubios Journal of Asian and International Bioethics , doctors were trying to come up with emergency transfusion substitutes that could be given to wounded soldiers at the front. Some imprisoned people were injected with horse's blood, sheep's blood, or even blood drawn from the heart of a corpse. 

Experiments with different blood groups were also performed, and extensive notes were taken on what occurs when various blood types are transfused into people with corresponding and non-corresponding blood types. It's possible that part of what we now know about hemolytic transfusion reactions came out of the Japanese experiments. 

Scientists also tried out various methods of transporting blood, experimenting with transfused blood that had been kept in a thermos or had been frozen and thawed. Ringer's solution, which is an isotonic solution used to restore blood circulation , was also experimented with as a blood transfusion substitute, as was seawater .

Vivisections without anesthesia

Since they had told the local population that they were constructing a lumber mill, Ishii and his associates referred to their human subjects as "maruta" or "logs." Some of the most notorious experiments that Unit 731 performed were vivisections on maruta. According to The Guardian , after being deliberately infected with various diseases, imprisoned people were cut open without the use of anesthesia so that doctors could study how diseases affected various organs. Ishii and his colleagues thought that if they used anesthesia or dead patients, their results would be compromised .

In order to recreate the conditions of battlefield surgery, imprisoned people were shot so that doctors could practice extracting bullets, and often, veterinary surgeons were used for the dissections. According to The Baltimore Sun , the doctors also practiced amputations, with some reports alleging that they  reattached limbs on the other side of the body.

In 1995, a doctor who'd performed some of the vivisections at Unit 731 agreed to speak to the  Chicago Tribune on the condition of anonymity: "He made this unimaginable sound, he was screaming so horribly. But then finally he stopped. This was all in a day's work for the surgeons, but it really left an impression on me because it was my first time."

Frostbite experiments

Frostbite experiments were undertaken at Unit 731 in order to figure out the most effective methods for treating the condition. According to Factories of Death   by Sheldon H. Harris, the Kwantung Army High Command reached out to Ishii requesting research on the effects of frostbite as they began anticipating war with the Soviet Union. Without delay, frostbite experiments quickly became commonplace.

These experiments were done every year during the coldest months as bodies were exposed to varying freezing temperatures and then underwent various attempts at defrosting. According to the Encyclopedia of Human Rights Vol. 1 by David P. Forsythe, imprisoned people would be tied up outside or sprayed with saltwater to induce frostbite. Sometimes, arms or legs would be dipped into water so that they'd freeze more quickly. 

In the Materials on the Trial of Former Servicemen of the Japanese Army Charged with Manufacturing and Employing Bacteriological Weapons , testimonies from researchers revealed how the frostbite experiments were performed. After the imprisoned people had gotten frostbite, they were forced to put the frostbitten appendage in water that was 5°C, and the temperature of the water was gradually increased. One Japanese guard noted how they could tell that a limb had frozen once it sounded like wood when it was struck with a stick. 

Experimenting with venereal diseases

Unit 731's microbiological research wasn't limited to biological warfare. Since syphilis afflicted many Japanese troops due to the prevalence of systematic rape and their abuse of "comfort women," researchers at Unit 731 wanted to better understand the affliction. In order to study the progression of the disease, imprisoned people at Unit 731 were purposefully infected with syphilis and gonorrhea to study the effects of venereal disease as it ravages the body. 

According to Pacific Atrocities Education , imprisoned people were either forced to sexually engage with a previously infected prisoner or were given syphilis through injections, although the transmission rates with injections were unreliable and quickly discontinued . Guards would hold the imprisoned people at gunpoint until they were satisfied with the act that had occurred.

Once the infection was successfully transmitted, researchers observed the progression of the disease and noted the stages as it advanced and affected the body. Researchers tracked external signs, and it was especially in these instances that vivisections were conducted in order to investigate how syphilis affected the internal organs at various stages.

Forced pregnancies

In addition to forcing imprisoned people to rape one another, guards would frequently force themselves upon their prisoners as well, often simply as  a way to kill time .

According to Pacific Atrocities Education , this frequently led to pregnancies, which were incorporated into the various human experiments done at Unit 731. The transmission of syphilis between mother and fetus was especially of interest for the researchers, and pregnant women were often infected with syphilis and cut open in order to see the effects on the fetus. The fetuses and babies were also used for various other experiments, like the research into frostbite.

Sometimes, people were forcibly impregnated so that various experiments could be conducted on pregnant people specifically. After the vivisections were completed, the bodies were burned so as to leave no evidence, though photographs of the experiments survive . No one knows how many people were "born" into Unit 731, but according to The New York Times , there were no survivors in the end.

Burgeoning biological warfare

Unit 731 was just one of many Japanese units concerned with biological warfare during World War II. While they occupied themselves with a variety of human experimentation, the main goal of the units was developing biological weapons. Unit Ei 1644 in Nanjing was another major biological warfare research center that studied a multitude of diseases and poisons.

According to The Guardian , Unit 731 cultivated, among others, cholera, plague, typhoid, and anthrax. To test their methods, Japanese planes would fly over Chinese villages and drop rice, cotton, or wheat sown with plague-infected fleas. CIA documents record one such incident occurring on October 27, 1940, when Japanese planes scattered wheat grains over Ningbo. On October 29, there was an outbreak of bubonic plague in the village, and within two days, 26 people had died . Tests were also done with anthrax bombs , though people often died from wounds inflicted by the bombs rather than via infection.

Testimonies from Materials on the Trial of Former Servicemen of the Japanese Army Charged with Manufacturing and Employing Bacteriological Weapons reveal that the various units were making at least 100 kilograms of anthrax, plague, typhoid, cholera each per month. In this case, that measure refers to the weight of the thick bacterial mass that was taken from the surface of the hard culture. While the amounts that they were producing weren't enough to launch a full-fledged biological attack, in 1941, efforts were ramped up to increase the mass production of bacteria .

Operation PX

One of the most ambitious projects of Unit 731 was Operation PX, also known as Operation Cherry Blossoms At Night. After having tested out dropping plague-infected fleas at Ningbo and Changde , the Japanese government hoped to expand their efforts onto the shores of the United States. This wasn't the first attempt by the Japanese to attack U.S. soil. According to Wired , the Japanese developed thousands of balloon bombs, one of which successfully drifted into Oregon and killed six people on May 5, 1945. But the logistics of biological warfare were considerably more overwhelming.

Developed by Ishii and approved by the Imperial Japanese government on March 26, 1945, Operation PX entailed dropping cargo filled with plague-infected fleas over Southern California. Fleas would infect rats, which would then infect food supplies  and spread the infections to people.

According to The Japan Times , the Imperial Japanese government planned to drop the cargo on San Diego, but after the United States  bombed Hiroshima and Nagasaki , leading to Japan's surrender, the plan simply never came to fruition. The timing was terrifyingly close, though. Operation Cherry Blossoms was to be executed on September 22, and the Japanese had surrendered just weeks earlier .

Unit 731 was swept under the rug by the United States

When Japan's defeat was imminent, orders were quickly given to destroy all the biological warfare facilities. Despite these efforts, floods of accusations and allegations of war crimes followed Japan's surrender. Ishii was repeatedly named, and eventually, he was tracked down at his home village in mid-January 1946. However, he wasn't arrested. Instead, the  U.S. government sent Arvo Thompson to Tokyo to question Ishii . Thompson and others interrogated Ishii for seven weeks, during which time Ishii portrayed his biological warfare research as a small-scale operation.

According to Factories of Death   by Sheldon H. Harris, the United States began their own biological weapons research not in response to Japan's research but out of fear of potential German research. While it is now known that Hitler prohibited the use of biological warfare, the United States wanted to be ready. But by 1942, at least one American medical journal had published a report about Japanese biological warfare in China.

Despite the fact that there was a great deal of evidence and an acknowledgement that the Japanese experiments were similar to those that the Germans were tried for, all prosecutions against Ishii and his associates were dropped. According to the Cambridge Quarterly of Healthcare Ethics , the United States' task force concluded that "the value to the U.S. of Japanese [biological warfare] data is of such importance to national security as to far outweigh the value accruing from 'war crimes' prosecution."

The Soviet Union shows the world a trial

After the United States decided not to pursue charges of war crimes against the Japanese researchers, the Soviet Union put on trials of their own. While the trials were derided by the United States as communist propaganda , they were able to establish beyond a reasonable doubt that the Japanese army had worked extensively with biological warfare and had conducted horrifying experiments on human beings. According to " Soviet War Crimes Policy in the Far East " by Valentyna Polunina, the Soviet Union might have belatedly decided to hold the trials once they realized that the U.S. wasn't going to share the information it had received from Ishii.

According to The Japan Times , while Soviet officials had been debating on what to do with Japanese prisoners of war, the United States secretly granted immunity to the researchers of Unit 731, infuriating the Soviet Union and inspiring them to hold trials of their own. The Khabarovsk War Crime Trials began on December 25, 1949, and lasted five days as they were pushed through Stalin's courts. In 1950, the Soviet Union published Materials on the Trial of Former Servicemen of the Japanese Army Charged with Manufacturing and Employing Bacteriological Weapons , which offered, in English, documents and testimony from the investigation.

Despite the show of the trials, though, it's likely that the Soviets also made a deal with the Japanese in exchange for information. While most Unit 731 researchers received 20 to 25 years, many were freed and quietly returned to Japan by 1956.

Aftermath and official government response

As knowledge of the biological warfare projects faded from memory, Japan refused to acknowledge the allegations of inhumane experimentation until 1984. Japanese textbooks mentioned Unit 731 briefly, but in 1997, a court ruled for the mentions to be deleted, claiming that "no reliable academic study, paper or publication is available for reference...therefore it was too early to address this issue in a textbook." Even when local governments held exhibitions about Unit 731, the national government continued to deny its existence. According to The Guardian , while Japan reluctantly admitted in the 1990s that Unit 731 had existed, they continued to refuse to discuss anything that had taken place in the camp.

According to The Japan Times , it wasn't until 2002 that the Tokyo District Court acknowledged Japan's use of biological warfare against China during World War II. Lawsuits had been filed in 1997 and 1998, demanding damages and an apology from the Japanese government for their role in biological warfare. However, while the court acknowledged that inhumane biological attacks had been carried out, Judge Koji Iwata rejected the plea for damages, stating that there was no precedent under international law for war damages being rewarded to victims. 

In 2018, the Japanese government released the names of the thousands of people who had worked at Unit 731, the first time that an official document revealing the names of the researchers was ever disclosed.