Unit 731: Chemical & Biological Warfare Division

Japan's Unit 731 outside of Harbin, Manchuria.

Sometimes I just find stuff out about Japan that just boggles the mind. This is one of those times.

One of the real reasons I wanted to go to Japan was to actually talk to a few WWII veterans there and get their opinion of the war. I did that and loved their refreshing candor in discussing how they had no hate for the enemy, and just wanted to go back home to their families safely. Granted I only sampled a small cross-section of the Japanese Imperial Army and Navy, but I still felt good about how the average Joe Suzuki wasn't a blood-thirsty killer, and was just merely a soldier in a war.

And then there's Unit 731... a secret Japanese military unit that is reported to have used Chinese prisoners for medical experiments so horrific that it would make the Nazi doctor Josef Mengele look like a saint.

I'm going to present this case with a small grain of salt. This was a secret military unit. Facts, such as they are, are not well publicized. Japan still denies the full extent of its participation in the following events. Did it occur? I wasn't there, of course, but there does seem to be a fair amount of evidence to say it not only occurred, but that more than one country prospered at the horrific results obtained from it.

Set up as a top-secret biological and chemical weapons facility during the Second Sino-Japanese War (starting in July 7, 1937) and World War Two (ending September 9, 1945), Unit 731 was a place of horror, becoming known as the Asian Auschwitz.

Officially, Unit 731 was known as the Epidemic Prevention and Water Supply Unit of the Kwantung Army (Kanto Army -関東軍 ) of Japan, but it had over 3,000 researchers, technicians, nurses and doctors, not including soldiers, to staff it.

Unofficially, Unit 731 is purported to have focused on human experimentation - the lethal kind - and it is estimated to have caused the death of some 200,000 civilians and military personnel– mostly Chinese and Koreans, but also South East Asians, Pacific Islanders and Allied P.o.W's (prisoners of war).

Hazmat suits were to used to move victims of germ tests.

Located within a six-kilometer square complex with 150 buildings just outside the city of Harbin, northeastern China (formerly Manchuria) , Unit 731 experimented on human beings via vivisection, amputations, germ warfare tests, explosive weapons testing, and much more, including on-purpose infected them with diseases including anthrax, cholera and the bubonic plague - all in the name of research science.

For example, on the frozen fields of Pingfang, northeast China, chained prisoners were led out. With their arms bare, they were subjected to a cold current of air to accelerate the freezing process. With a short stick, the prisoners would then be struck on the arm to ensure their limbs had frozen. It had to sound like a wooden plank being struck before the effects of frostbite could be studied,  

Now 200,000 victims sounds like an absurd amount of personal testing - but it wasn't always a one-on-one test. By the time the war was over, 3,000 prisoners died directly from the experiments, and some 200,000 citizens died through biological warfare experiments. Apparently each year some 600 prisoners were delivered during the 12 months to the facility by the Kempeitai (a special military police force).

One part of the Unit 731 complex was the Ro Block, a place down in the basement specifically reserved for experimentation on live human prisoners - men, women, children, even pregnant women and their unborn were not off-limits - who were known as maruta or 'logs of wood'.

Sheldon H. Harris, a historian on Unit 731, explained in a History Channel television documentary how the people tortured and killed were treated as objects: “These scientists had a weird sense of humor,” Harris revealed. “They referred to their victims as “matures”, which, loosely translated, is logs, and that’s how they thought about them, as pieces of wood, not as humans. They could cut them up; they could burn them in a fireplace… If they ran short of candidates, the secret police would just literally sweep the streets of the city and pick up enough candidates for the lab.”

Matsumoto Shoichi (surname first), a Unit 731 bomber pilot, said: "There were always 2,000 or 3,000 logs (people) prepared. There were two burning places and there were always burning dead bodies.”

Examples of some of the cruelties inflicted upon these people include: 

• purposely infected with cholera, typhoid, anthrax, plague, syphilis;
• the cutting up of still alive victims to see the successive affects of hemorrhagic fever;
• Siphoning of blood to be replaced with horse blood;
• experiments to see pain thresholds and death via guns;
• testing to death via flame-throwers; 
• testing to death via explosives; 
• testing to death on gangrene via gases; 
• testing to death via bombardment of high levels of X-Rays; 
• testing to death via giant spinning centrifuges;
• testing in sealed high-pressure chambers until eyes popped out; 
• testing via electrocution; 
• testing via dehydration; 
• testing via freezing; 
• testing to death via boiling.

Autopsies were performed on the dead and living at Unit 731.

According to reports, two prisoners were placed on a diet consisting of nothing but water and biscuits and then worked non-stop. They would be forced to walk the Unit 731 compound whilst loaded with 20-kilogram sandbags on their back until they died. While one lasted longer than the other by a month, this was Unit 731 research into malnutrition. 

One of the medical researchers involved with Unit 731 explained how vivisection was performed on people: “I was ordered to wash that person’s body with a deck brush before he or she was taken into the dissection room naked by a member of the special team,” he recalled. “The first time, I trembled. One team member was listening to the heartbeat with a stethoscope. One was standing holding a knife. The moment the stethoscope was removed from the ear, a knife went into the body. I did not know, but according to doctors, this timing was very important, because if the timing was wrong, we could get blood all over us, and then we could get infected.”

Some of the most violent tests were connected with trying to find the best ways of treating Japanese shrapnel injuries sustained during fighting. Prisoners were tied to wooden stakes positioned around a bomb at various distances before the explosive was detonated. Those who survived would have surgery performed on them; the rest went for autopsies.

Other prisoners literally became human targets for testing other weaponry such as flamethrowers, not to mention germ-releasing bombs and chemical weapons.

Vivisection was performed on men, women and children – who had been infected with diseases – without the use of anesthetic. Organs were removed from test subjects while they were still alive so that decomposition would not alter the results as was feared might happen.

Regarding germ warfare testing, the aim was to find a mode of delivering such pathogens that would cause the most widespread death and devastation, and several were developed – among them the defoliation bacilli bomb and the flea bomb.

Fleas carrying the bubonic plague – along with anthrax, typhoid and dysentery germs - were dropped in these bombs, some of which were designed with porcelain shells (apparently a brainchild of Ishii himself).

When the bio-weapons attacks were launched, the infected items were released from planes to fall on areas of China not occupied by Japan, where they contaminated agriculture and water supplies. What’s more, the diseases were actually administered to children in villages by way of deadly poisoned candies. In testing the effects of their work, scientists wearing hazmat suits would inspect the dying victims.

Prisoners were also infected with STDs (sexually-transmitted diseases) such as gonorrhea and syphilis to see how the diseases spread in the body without treatment. Meanwhile, fleas needed for the bio-attacks involving the bubonic plague were bred by the container-full, as were chemicals and other biological agents.

Bodies piled outside in the freezing cold at Unit 731.

Some infected prisoners were sliced open to have invasive surgery performed on them while alive; others had limbs severed to study blood loss. Apparently some researchers are known to have re-attached amputated arms and legs to victims’ bodies, and to have frozen and thawed some limbs so that they could study the effects of the rot and gangrene that set in.

Discussing some of the methods used inside the unit, Sheldon H. Harris said: “They had refrigerator chambers, and also, in Manchuria, the winters here were very severe, 40 to 50 degrees below zero Fahrenheit, and they would expose prisoners – various parts of their bodies – to these temperatures, freeze them and then try various techniques to literally dehydrate them, to see what was the most effective way of dealing with frostbite, so that that could be used in warfare as well – both to protect Japanese troops as well as to affect the enemy.”

There were many other fiendish experiments acted out on the thousands of prisoners incarcerated in Unit 731. These included testing chemical weapons on people trapped inside gas chambers; spinning victims in giant centrifuges until they perished; hanging individuals upside down to test their endurance before they choked to death; and injecting air into prisoners’ arteries and horse urine into their kidneys.

Lt. Gen. Ishii Shiro, Unit 731.

Unit 731 was the creation of Lieutenant-General Ishii Shiro (surname first) (石井 四郎, b: June 25, 1892 – d: October 9, 1959), a microbiologist born in Shibayama Village in the Sanbu District of Chiba-ken (Chiba Prefecture). Studying medicine at Kyoto Imperial University, he was a smart, if not brash individual. 


In 1922, he was assigned to the 1st Army Hospital and Army Medical School in Tokyo, and two years later went back to Kyoto Imperial University for post-graduate medicine. In 1928, he traveled Europe over a two-year span to study the effect of biological and chemical warfare caused by WWI. His findings helped him win the patronage of Araki Sadao, then the Minister of the Army.  

In 1932, he began his preliminary experiments in biological warfare as a secret project for the Japanese military at Zhongma Fortress (Unit Tōgō) - all under the overview of Sadao.

Unit Tōgō did indeed do real and legitimate (read here - legal) medical research on vaccines and public health, but with Ishii's need to conduct secret biological warfare testing, it was felt the facility was too close to a highly populated area. A second site, selected by Ishii about 100 kilometers to the south of Harbin at the village of Beiyinhe caused the forcible relocation of the villagers. The village was burned down and a large tract of land was fenced off.

Prisoner/test subject at Unit 731.

Chinese labor was used to build the facility including common criminals, captured bandits and anti-Japanese partisans and political prisoners and people rounded up for suspicious behavior by the Kempeitai (a special military police force). 

At this new facility, bizarre experiments were conducted, despite the fact that the prisoners were well fed on their usual diet of rice or wheat with meat, fish and occasionally even alcohol – with the intent of starting experiments with the subjects in their usual state of health. In some experiments, the prisoners were drained of blood over a few days to examine how their condition would deteriorate. Other test subjects underwent water or food deprivation. Those who survived, but were too weak to work were executed.

In August 1934, one prisoner, named Li, managed to overpower his guard, seize the keys and free about forty of his fellow prisoners. A heavy rain had knocked out the facility's electricity, deactivating the searchlights and electric fence, but despite 10 men being shot and others recaptured, some did escape to tell about the horrors being conducted there.

As a result of this publicity, Zhongma Fortress (Unit Tōgō) was closed down, and its activities transferred in 1936 to a new site closer to Harbin called Pingfang (Heibo), which came to be known as Unit 731.

An autopsy at Unit 731.

On 9 February 1939, Ishii gave a lecture on bacteriological warfare in the War Ministry Grand Conference Hall in Tokyo. One of the attendees was prince Yasuhito Chichibu, Hirohito's (the 124th Emperor of Japan) brother, who also watched vivisection demonstrations by Ishii.


From 1940, Ishii was appointed Chief of the Biological Warfare Section of the Kwantung Army, holding that post along that of the Bacteriological Department of the Army Medical Academy.

In 1942, Ishii began field tests of germ warfare agents developed, and various methods of weapons dispersion on Chinese prisoners of war and operationally on battlefields and against civilians in Chinese cities.

From 1942-1945, Ishii was Chief of the Medical Section of the Japanese First Army^.

Part of Ishii's fame came from the invention of a water filter that would be used by the Japanese military in the field. He once reportedly demonstrated the effectiveness of the filter to Emperor Hirohito by urinating through it, and offering the result to the Hirohito to drink. The Emperor declined, so Ishii drank it himself.

In 1945, in the final days of the Pacific War, Japanese troops blew-up Unit 731 to destroy evidence of the research done there. Ishii also ordered the remaining 150 remaining prisoners killed. 

A crematorium at Unit 731 destroyed by Japan.

Here's where things get sketchy, but not wholly unbelievable, as the U.S. became involved. As an aside, it is known that many Nazi Germany scientists who work on the rocket programs were given safe haven as scientists - not as war criminals - to provide research and data that helped the U.S. weapons and space programs.   

When a country becomes engaged in a war it later wins, why should it not also revel in the spoils of war?

Feeling that the germ warfare research was valuable, the U.S. arranged a deal with Japan. In 1947, U.S. General Douglas MacArthur wrote that: “additional data, possibly some statements from Ishii, probably can be obtained by informing Japanese involved that information will be retained in intelligence channels and will not be employed as ‘War Crimes’ evidence.”

Crappy MacArthur grammar aside, by granting immunity to Ishii and other scientists working under him, the U.S. tried to ensure no other country could get hold of this data. However, the U.S.S.R. gathered some facts after prosecuting 12 leaders and scientists from Unit 731 in war crimes trials held in 1949. Those found guilty were sentenced to between two and 25 years in a labor camp, and the Soviets built a biological weapons facility in Sverdlovsk using the data collected.

Meanwhile, Ishii was allowed to move to Maryland, U.S. where he worked as a bio-weapons researcher. No war-crimes trial for him!

Ishii, lived in peace and quiet to the ripe old age of 67, when he died of throat cancer.

Ishii examines a test subject of Unit 731.

It can be argued that China suffered longer than other countries in the days leading up to WWI and during it, starting with Japan's occupation of Manchuria. While the "Rape of Nanking" has become well documented, historical evidence documenting the extent of Japan's atrocities during World War II pales to the evidence against Nazi Germany's war crimes.

Author Hal Gold has written a book on the whole sordid affair entitled Unit 732 Testimony that was written after Japan had organized a national exhibit about Unit 731 to remind its citizens of the horrible crimes Japan had committed during the war; a historical fact that had been virtually ignored.

Although some remorse is indicated by Japan, most believe the unit was merely performing their wartime duty for Japan, and thus has nothing to apologize for. Key evidence of this can be found during a court case from 10 years ago. 

On August 28, 2002, in a case that lasted five years, three judges of the Tokyo District Court rejected a claim for an apology and compensation by 180 Chinese who were either victims or the family of victims of Unit 731.

This was, however, the first time,a Japanese court had acknowledged that Unit 731 and other units had engaged in "cruel and inhumane" biological warfare in China, costing many lives.

But, the judges claimed there was no legal basis for the plaintiffs' claim, as all compensation issues were settled by a treaty with China in 1972.

Just another day at Unit 731.

Testimony during the court case was heard by a former member of Unit 731, Shinozuka Yoshio (surname first) who felt great remorse.

One of Shinozuka's job at Unit 731 was to scrub test subjects down before the vivisection.

"I still remember clearly the first live autopsy I participated in," he recalled. "I knew the Chinese individual we dissected alive because I had taken his blood once before for testing. At the vivisection, I could not meet his eyes because of the hate he had in his glare at me."

The victim had been infected with the plague, and was totally black. Shinozuka was reluctant to use the brush on the man's face.

"Watching me, the chief pathologist, with scalpel in hand, impatiently signalled me to hurry up," he recalled. "I closed my eyes and forced myself to scrub the man's face with the deck brush. The chief pathologist listened to the man's heartbeat with his stethoscope and then the procedure started."

The case before the Tokyo court also heard from the victims, and family of the victims, in villages and towns infected by the plague and cholera between 1940 and 1942.

Bombs were used to deliver Unit 731 devised germ warfare.

Peize Xue was a young boy in Jiangshan when the Japanese infected the area with cholera. He recalled how his sister's three children had been struck down: "The three little ones died such tragic deaths. They were poisoned by the Japanese army," she sobbed. "Before Shuanglan (aged eight) passed away, she asked me, lying limply on her bed, to build a small casket for her."

It was only in 1981 that international attention refocused on these events when American journalist, John W. Powell junior published A Hidden Chapter in History, alleging an American cover-up.

In his authoritative Factories of Death: Japanese Biological Warfare 1932-45, and the American Cover-up, Sheldon H. Harris recounts that the matter was raised only once at the Tokyo war crimes tribunal in 1946-48.

At the war crime tribunal, an American counsel assisting the Chinese, David N. Sutton, stunned the war crimes tribunal by saying: "The enemy . . . took our countrymen as prisoners and used them for drug experiments. They would inject various types of toxic bacteria into their bodies, and then perform experiments on how they reacted . . . this was an act of barbarism by our enemy."

The presiding chief judge, Australia's Sir William Webb, asked: "Are you trying to tell us about a poison liquid being administered? Are you trying to provide more evidence? This is a new fact that you have presented before we judges."

The writer Harris says that after a brief pause, Webb said: "How about letting this item go?" Sutton replied: "Well, then, I'll leave it." The issue never surfaced again, Harris writes.

The immunity granted to those in Unit 731 saw the doctors involved return to mainstream Japanese society. In 1989, the now-defunct Japanese magazine Days Japan revealed how those who had escaped prosecution had gone on to take some of the most prestigious positions in the Japanese medical community.

The man who succeeded Ishii Shiro as commander of Unit 731, Dr. Kitani Masaji (surname first) became head of Japan's largest pharmaceutical company, the Green Cross. Others took up posts heading university medical schools or worked within Japan's health ministry.

During the court trial Yamane Kazuyo who lectures at Japan's Kochi University on peace studies says she and other Japanese traveled to China in 1998 to find out more about Unit 731. "Because we didn't have any means to know what really happened, we decided to go and try to know what really happened," she says noting that they spoke to people who had lost family members because of the biological warfare experiments.

"We felt really guilty as Japanese," she says adding that she believes the Japanese Government should apologize and compensate the victims of the "terrible damage" done during the war in Asia. "That's what we citizens think. But I think there is a huge gap between the citizens and the Japanese Government."

In the only official comment on the day of the decision, the Japanese Justice Ministry said the court's decision verified the validity of the Japanese Government's position in refusing compensation and an apology to the victims of Unit 731.

Files compiled by Andrew Joseph