Unit 731

Unit 731
The Unit 731 complex. Two prisons are hidden in the center of the main building.
Location	Pingfang, Harbin, Heilungkiang, Manchukuo
Coordinates	45°36′30″N 126°37′55″E
Date	1935–1945
Attack type	Human experimentation Biological warfare Chemical warfare
Weapon(s)	Biological weapons Chemical weapons Explosives
Deaths	Estimated 200,000 or 300,000–400,000 or higher from biological warfare Over 3,000 from inside experiments (not including branches, 1940–1945 only):20 At least 10,000 prisoners died
Perpetrator(s)	Surgeon General Shirō Ishii Lt. General Masaji Kitano Epidemic Prevention and Water Purification Department

Unit 731, short for Manshu Detachment 731, was a unit of the Imperial Japanese Army that engaged in unethical and deadly human experimentation and use of biological and chemical weapons during the Second Sino-Japanese War (1937–1945) and World War II. Based in Japanese-occupied China, it was responsible for some of the most notorious war crimes committed by the armed forces of Imperial Japan, including anthrax, cholera, and bubonic plague attacks on both military and civilian populations; vivisection of men, women, children and infants (often without anesthesia); testing of grenades and flamethrowers on people; and subjecting victims to food and water deprivation, low pressure, chemical agents, frostbite, amputation and limb reattachment, being buried alive, and other atrocities. Because Shirō Ishii was director of Unit 731, the division has also been referred to as the Ishii Unit.

Overview

Unit 731 was active in Japanese-occupied territory in Asia, notably Manchuria. The Empire of Japan first invaded Manchuria in 1931, and in 1932 established the puppet state of Manchukuo. Japan occupied other areas in Asia during the Second Sino-Japanese War and the Second World War.

The Second Sino-Japanese War (1937–1945) was a military conflict that was primarily waged between the Republic of China (1912–1949) and the Empire of Japan. The war made up the Chinese theater of the wider Pacific Theater of the Second World War. The beginning of the war is conventionally dated to the Marco Polo Bridge Incident on July 7, 1937, when a dispute between Japanese and Chinese troops in Beijing escalated into a full-scale invasion. This full-scale war between the Chinese and the Empire of Japan is often regarded as the beginning of World War II in Asia. After the Japanese invasion of Malaya and attack on Pearl Harbor in 1941, the war merged with other conflicts that are generally categorized under those conflicts of World War II. Some scholars consider the European theatre of World War II and the Pacific War to be entirely separate, albeit concurrent, wars. Other scholars consider the start of the full-scale Second Sino-Japanese War in 1937 to have been the beginning of World War II. Following the Marco Polo Bridge Incident, the Japanese scored major victories, capturing Beijing, Shanghai, and the Chinese capital of Nanjing in 1937. After failing to stop the Japanese in the Battle of Wuhan, the Chinese central government was relocated to Chongqing (Chungking) in the Chinese interior.

The formation of Unit 731 traces to 1932, when Surgeon General Shirō Ishii, chief medical officer of the Imperial Japanese Army, organized a secret research group, the "Tōgō Unit," for chemical and biological experimentation in Manchuria. In 1936, Emperor Hirohito authorized the expansion of this unit and its integration into the Kwantung Army as the Epidemic Prevention Department (Barenblat 2004). In 1940, it became known as the "Epidemic Prevention and Water Purification Department of the Kwantung Army (Tanaka 1996), or Unit 731 for short. Unit 731 (731部隊, Nana-san-ichi Butai), short for Manshu Detachment 731, is also known as the Kamo Detachment (trial materials ) and and Ishii Unit (CIA). Unit 731 was based in the Pingfang district of Harbin, the largest city in the Japanese puppet state of Manchukuo and had active branch offices throughout China and Southeast Asia. Note that the Japanese word butai is variously translated with military terms such as "unit", "detachment", "regiment" or "company".

Unit 731 was commanded until the end of World War II by General Ishii. The facility itself was built in 1935 as a replacement for the Zhongma Fortress, and Ishii and his team used it to expand their capabilities. The program received generous support from the Japanese government until the end of the war in 1945. Unit 731 and the other units of the Epidemic Prevention and Water Purification Department operated biological weapon production, testing, deployment and storage facilities. They routinely conducted tests on human beings (who were internally referred to as "logs"). Additionally, the biological weapons were tested in the field on cities and towns in China. Estimates of those who were killed by Unit 731 and its related programs range up to half a million people.

The researchers in Unit 731 were secretly given immunity by the United States in exchange for the data which they gathered during their human experimentation (Gold 2003). Other researchers that the Soviet forces managed to arrest first were tried at the Khabarovsk War Crime Trials in 1949. The Americans did not try the researchers so that the information and experience gained in bio-weapons could be co-opted into their biological warfare program, much as they had done with Nazi researchers in Operation Paperclip (Harris 2002). Victim accounts were then largely ignored or dismissed in the west as communist propaganda (Brody et al. 2014).

Formation

Building on the site of the Harbin bioweapon facility of Unit 731

In 1932, Surgeon General Shirō Ishii (石井四郎, Ishii Shirō), chief medical officer of the Imperial Japanese Army and protégé of Army Minister Sadao Araki was placed in command of the Army Epidemic Prevention Research Laboratory (AEPRL). Ishii organized a secret research group, the "Tōgō Unit", for chemical and biological experimentation in Manchuria. Ishii had proposed the creation of a Japanese biological and chemical research unit in 1930, after a two-year study trip abroad, on the grounds that Western powers were developing their own programs.

One of Ishii's main supporters inside the army was Colonel Chikahiko Koizumi, who later became Japan's Health Minister from 1941 to 1945. Koizumi had joined a secret poison gas research committee in 1915, during World War I, when he and other Imperial Japanese Army officers were impressed by the successful German use of chlorine gas at the Second Battle of Ypres, in which the Allies suffered 5,000 deaths and 15,000 wounded as a result of the chemical attack.

Zhongma Fortress

Unit Tōgō was implemented in the Zhongma Fortress, a prison/experimentation camp in Beiyinhe, a village 100 km (62 mi) south of Harbin on the South Manchuria Railway. Prisoners were generally well fed on the usual diet of rice or wheat, meat, fish, and occasionally even alcohol, with the intent of having prisoners in their normal state of health at the beginning of experiments. Over several days, prisoners were eventually drained of blood and deprived of nutrients and water. Their deteriorating health was recorded. Some were also vivisected. Others were deliberately infected with plague bacteria and other microbes.

In the autumn of 1934, a prison break, which jeopardized the facility's secrecy along with a later explosion (believed to be sabotage) in 1935 led Ishii to shut down Zhongma Fortress. He then received authorization to move to Pingfang, approximately 24 km (15 mi) south of Harbin, to set up a new, much larger facility.

Unit 731

In 1936, Emperor Hirohito authorized by decree the expansion of this unit and its integration into the Kwantung Army as the Epidemic Prevention Department. It was divided at that time into the "Ishii Unit" and "Wakamatsu Unit" with a base in Hsinking. From August 1940, the units were known collectively as the "Epidemic Prevention and Water Purification Department of the Kwantung Army (関東軍防疫給水部本部)" or "Unit 731" (満州第731部隊) for short.

A close up photo of the Unit 731 square building taken by the aviation and photography class of Unit 731 in 1940

Other units

In addition to the establishment of Unit 731, the decree also called for the establishment of an additional biological warfare development unit called the Kwantung Army Military Horse Epidemic Prevention Workshop (later referred to as Manchuria Unit 100) and a chemical warfare development unit called the Kwantung Army Technical Testing Department (later referred to as Manchuria Unit 516). After the Japanese invasion of China in 1937, sister chemical and biological warfare units were founded in major Chinese cities, and were referred to as Epidemic Prevention and Water Supply Units. Detachments included Unit 1855 in Beijing, Unit Ei 1644 in Nanjing, Unit 8604 in Guangzhou and later, Unit 9420 in Singapore. All of these units comprised Ishii's network, and at its height in 1939, was composed of more than 10,000 personnel. Medical doctors and professors from Japan were attracted to join Unit 731 by the rare opportunity to conduct human experimentation and strong financial support from the Army.

Activities

A special project code-named Maruta used human beings for experiments. Test subjects were gathered from the surrounding population and were sometimes euphemistically referred to as "logs" (丸太, maruta), used in such contexts as "How many logs fell?". This term originated as a joke on the part of the staff because the official cover story for the facility given to the local authorities was that it was a lumber mill. However, in an account by a man who worked as a junior uniformed civilian employee of the Imperial Japanese Army in Unit 731, the project was internally called "Holzklotz", which is a German word for log. In a further parallel, the corpses of "sacrificed" subjects were disposed of by incineration. Researchers in Unit 731 also published some of their results in peer-reviewed journals, writing as though the research had been conducted on non-human primates called "Manchurian monkeys" or "long-tailed monkeys".

The test subjects were selected to give a wide cross-section of the population and included common criminals, captured bandits, anti-Japanese partisans, political prisoners, the homeless and mentally handicapped, and also people rounded up by the Kempeitai military police for alleged "suspicious activities". They included infants, men, the elderly, and pregnant women. The members of the unit included approximately 300 researchers, including doctors and bacteriologists. Many had been desensitized to performing cruel experiments from experience in animal research.

Nakagawa Yonezo, professor emeritus at Osaka University, studied at Kyoto University during the war, and, while he was there, watched footage of human experiments and executions from Unit 731. He testified about the playfulness of the experimenters:

"Some of the experiments had nothing to do with advancing the capability of germ warfare, or of medicine. There is such a thing as professional curiosity: ‘What would happen if we did such and such?’ What medical purpose was served by performing and studying beheadings? None at all. That was just playing around. Professional people, too, like to play."

Prisoners were injected with diseases, disguised as vaccinations, to study their effects. To study the effects of untreated venereal diseases, male and female prisoners were deliberately infected with syphilis and gonorrhea, then studied. Prisoners were also repeatedly subject to rape by guards.

Vivisection

Thousands of men, women, children and infants interned at prisoner of war camps were subjected to vivisection, often without anesthesia and usually ending with the death of the victim. In a video interview, former Unit member Okawa Fukumatsu admitted to having vivisected a pregnant woman. Vivisections were performed on prisoners after infecting them with various diseases. Researchers performed invasive surgery on prisoners, removing organs to study the effects of disease on the human body.

Human Dissection Experiment Room

Prisoners had limbs amputated in order to study blood loss. Those limbs that were removed were sometimes re-attached to the opposite sides of the body. Some prisoners had their stomachs surgically removed and the esophagus reattached to the intestines. Parts of organs, such as the brain, lungs, and liver, were removed from some prisoners. Imperial Japanese Army surgeon Ken Yuasa suggests that the practice of vivisection on human subjects was widespread even outside Unit 731, estimating that at least 1,000 Japanese personnel were involved in the practice in mainland China.

Biological warfare

The ruins of a boiler building on the site of the bioweapon facility of Unit 731

Unit 731 and its affiliated units (Unit 1644 and Unit 100 among others) were involved in research, development and experimental deployment of epidemic-creating biowarfare weapons in assaults against the Chinese populace (both military and civilian) throughout World War II. Plague-infected fleas, bred in the laboratories of Unit 731 and Unit 1644, were spread by low-flying airplanes upon Chinese cities, including coastal Ningbo and Changde, Hunan Province, in 1940 and 1941. This military aerial spraying killed tens of thousands of people with bubonic plague epidemics. An expedition to Nanking involved spreading typhoid and paratyphoid germs into the wells, marshes, and houses of the city, as well as infusing them into snacks to be distributed among the locals. Epidemics broke out shortly after, to the elation of many researchers, where it was concluded that paratyphoid fever was "the most effective" of the pathogens.^{:xii, 173}

At least 12 large-scale field trials of biological weapons were performed, and at least 11 Chinese cities were attacked with biological agents. An attack on Changda in 1941 reportedly led to approximately 10,000 biological casualties and 1,700 deaths among ill-prepared Japanese troops, with most cases due to cholera. Japanese researchers performed tests on prisoners with bubonic plague, cholera, smallpox, botulism, and other diseases. This research led to the development of the defoliation bacilli bomb and the flea bomb used to spread bubonic plague. Some of these bombs were designed with porcelain shells, an idea proposed by Ishii in 1938.

These bombs enabled Japanese soldiers to launch biological attacks, infecting agriculture, reservoirs, wells, as well as other areas with anthrax, plague-carrier fleas, typhoid, dysentery, cholera or other deadly pathogens. During biological bomb experiments, researchers dressed in protective suits would examine the dying victims. Infected food supplies and clothing were dropped by airplane into areas of China not occupied by Japanese forces. In addition, poisoned food and candies were given to unsuspecting victims.

During the final months of World War II, Japan planned to use plague as a biological weapon against San Diego, California. The plan was scheduled to launch on September 22, 1945, but Japan surrendered five weeks earlier. Plague fleas, infected clothing and infected supplies encased in bombs were dropped on various targets. The resulting cholera, anthrax, and plague were estimated to have killed at least 400,000 Chinese civilians. Tularemia was also tested on Chinese civilians.

Due to pressure from numerous accounts of the bio-warfare attacks, Chiang Kai-shek sent a delegation of army and foreign medical personnel in November 1941 to document evidence and treat the afflicted. A report on the Japanese use of plague-infested fleas on Changde was made widely available the following year, but was not addressed by the Allied Powers until Franklin D. Roosevelt issued a public warning in 1943 condemning the attacks.

Weapon testing

Human targets were used to test grenades positioned at various distances and in various positions. Flamethrowers were tested on people. Victims were also tied to stakes and used as targets to test pathogen-releasing bombs, chemical weapons, shrapnel bombs with varying amounts of fragments, and explosive bombs as well as bayonets and knives.

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—Unit 731, Nightmare in Manchuria

Other experiments

In other tests, subjects were deprived of food and water to determine the length of time until death; placed into low-pressure chambers until their eyes popped from the sockets; experimented upon to determine the relationship between temperature, burns, and human survival; hung upside down until death; crushed with heavy objects; electrocuted; dehydrated with hot fans; placed into centrifuges and spun until death; injected with animal blood; exposed to lethal doses of x-rays; subjected to various chemical weapons inside gas chambers; injected with sea water; and burned or buried alive. In addition to chemical agents, the properties of many different toxins were also investigated by the Unit. To name a few, prisoners were exposed to tetrodotoxin (pufferfish or fugu venom); heroin; Korean bindweed; bactal; and castor-oil seeds (ricin). Massive amounts of blood were drained from some prisoners in order to study the effects of blood loss according to former Unit 731 vivisectionist Okawa Fukumatsu. In one case, at least half a litre of blood was drawn at two to three-day intervals.

Unit 731 also performed transfusion experiments with different blood types. Unit member Naeo Ikeda wrote:

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Unit 731 tested many different chemical agents on prisoners, and had a building dedicated to gas experiments. Some of the agents tested were: mustard gas; lewisite; cyanic acid gas; white phosphorus; adamsite; and phosgene gas. A former army major and technician gave the following testimony anonymously (at the time of the interview, this man was a professor emeritus at a national university):

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Unit 100 also experimented with toxic gas. Phone booth-like tanks were used as portable gas chambers for the prisoners. Some were forced to wear various types of gas masks, others wore military uniform and some had no clothes on at all.

Some of the tests have been described as "psychopathically sadistic, with no conceivable military application". For example, one experiment documented the time it took for three-day-old babies to freeze to death.

Unit 731 also tested chemical weapons on prisoners in field conditions. A report authored by unknown researcher in the Kamo Unit (Unit 731) describes a large human experiment of yperite gas (mustard gas) on September 7—10, 1940. Twenty subjects were divided into three groups and placed in combat emplacements, trenches, gazebos, and observatories. One group was clothed with Chinese underwear, no hat, and no mask, and was subjected to as much as 1,800 field gun rounds of yperite gas over 25 minutes. Another group was clothed in summer military uniform and shoes; three had masks and another three had no mask. They also were exposed to as much as 1,800 rounds of yperite gas. A third group was clothed in summer military uniform, three with masks and two without masks, and were exposed to as much as 4,800 rounds. Then their general symptoms and damage to skin, eye, respiratory organs, and digestive organs were observed at 4 hours, 24 hours, and 2, 3, and 5 days after the shots. Injecting the blister fluid from one subject into another subject and analyses of blood and soil were also performed. Five subjects were forced to drink a solution of yperite and lewisite gas in water, with or without decontamination. The report describes conditions of every subject precisely without mentioning what happened to them in the long run. The following is an excerpt of one of these reports:

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Frostbite testing

Army Engineer Hisato Yoshimura conducted experiments by taking captives outside, dipping various appendages into water of varying temperatures, and allowing the limb to freeze. Once frozen, Yoshimura would strike their affected limbs with a short stick, "emitting a sound resembling that which a board gives when it is struck'". Ice was then chipped away, with the affected area being subjected to various treatments such as being doused in water, exposed to the heat of fire etc.

Members of the Unit referred to Yoshimura as a “scientific devil” and a “cold blooded animal” because he would conduct his work with strictness. Naoji Uezono, a member of Unit 731, described in a 1980s interview a grisly scene where Yoshimura had “two naked men put in an area 40-50 degrees below zero and researchers filmed the whole process until [the subjects] died. [The subjects] suffered such agony they were digging their nails into each other’s flesh”. Yoshimura’s lack of remorse was evident in an article he wrote for the Journal Of Japanese Physiology in 1950 in which he admitted to using 20 children and a 3-day-old infant in experiments which exposed them to zero-degree-celsius ice and salt water. Although this article drew criticism, Yoshimura denied any guilt when contacted by a reporter from the Mainichi Shinbun (a Japanese newspaper). Yoshimura developed a “resistance index of frostbite” based on the mean temperature 5 to 30 minutes after immersion in freezing water, the temperature of the first rise after immersion, and the time until the temperature first rises after immersion. In a number of separate experiments it was then determined how these parameters depend on the time of day a victim’s body part was immersed in freezing water, the surrounding temperature and humidity during immersion, how the victim had been treated before the immersion (“after keeping awake for a night”, “after hunger for 24 hours”, “after hunger for 48 hours”, “immediately after heavy meal”, “immediately after hot meal”, “immediately after muscular exercise”, “immediately after cold bath”, “immediately after hot bath”), what type of food the victim had been fed over the five days preceding the immersions with regard to dietary nutrient intake (“high protein (of animal nature)”, “high protein (of vegetable nature)”, “low protein intake”, and “standard diet”) and salt intake (45 g NaCl per day, 15 g NaCl per day, no salt). This original data is seen in the attached figure.

Scan Of Yoshimura Hisato's Frostbite Research Data

Syphilis

Unit members orchestrated forced sex acts between infected and non-infected prisoners to transmit the disease, as the testimony of a prison guard on the subject of devising a method for transmission of syphilis between patients shows:

"Infection of venereal disease by injection was abandoned, and the researchers started forcing the prisoners into sexual acts with each other. Four or five unit members, dressed in white laboratory clothing completely covering the body with only eyes and mouth visible, rest covered, handled the tests. A male and female, one infected with syphilis, would be brought together in a cell and forced into sex with each other. It was made clear that anyone resisting would be shot."

After victims were infected, they were vivisected at different stages of infection, so that internal and external organs could be observed as the disease progressed. Testimony from multiple guards blames the female victims as being hosts of the diseases, even as they were forcibly infected. Genitals of female prisoners that were infected with syphilis were called "jam filled buns" by guards.

Some children grew up inside the walls of Unit 731, infected with syphilis. A Youth Corps member deployed to train at Unit 731 recalled viewing a batch of subjects that would undergo syphilis testing: "one was a Chinese woman holding an infant, one was a White Russian woman with a daughter of four or five years of age, and the last was a White Russian woman with a boy of about six or seven." The children of these women were tested in ways similar to their parents, with specific emphasis on determining how longer infection periods affected the effectiveness of treatments.

Rape and forced pregnancy

Female prisoners were forced to become pregnant for use in experiments. The hypothetical possibility of vertical transmission (from mother to child) of diseases, particularly syphilis, was the stated reason for the torture. Fetal survival and damage to mother's reproductive organs were objects of interest. Though "a large number of babies were born in captivity", there have been no accounts of any survivors of Unit 731, children included. It is suspected that the children of female prisoners were killed after birth or aborted.

While male prisoners were often used in single studies, so that the results of the experimentation on them would not be clouded by other variables, women were sometimes used in bacteriological or physiological experiments, sex experiments, and as the victims of sex crimes. The testimony of a unit member that served as a guard graphically demonstrated this reality:

"One of the former researchers I located told me that one day he had a human experiment scheduled, but there was still time to kill. So he and another unit member took the keys to the cells and opened one that housed a Chinese woman. One of the unit members raped her; the other member took the keys and opened another cell. There was a Chinese woman in there who had been used in a frostbite experiment. She had several fingers missing and her bones were black, with gangrene set in. He was about to rape her anyway, then he saw that her sex organ was festering, with pus oozing to the surface. He gave up the idea, left and locked the door, then later went on to his experimental work."

Prisoners and victims

In 2002, Changde, China, site of the plague flea bombing, held an "International Symposium on the Crimes of Bacteriological Warfare" which estimated that the number of people killed by the Imperial Japanese Army germ warfare and other human experiments was around 580,000.^{:xii, 173} The American historian Sheldon H. Harris states that over 200,000 died. In addition to Chinese casualties, 1,700 Japanese troops in Zhejiang during Zhejiang-Jiangxi campaign were killed by their own biological weapons while attempting to unleash the biological agent, indicating serious issues with distribution.

At least 3,000 men, women, and children^:117 —from which at least 600 every year were provided by the Kempeitai were subjected to experimentation conducted by Unit 731 at the camp based in Pingfang alone, which does not include victims from other medical experimentation sites, such as Unit 100. Although 3,000 internal victims is the widely accepted figure in the literature, former Unit member Okawa Fukumatsu refuted it in a video interview. He stated that there were at least over 10,000 victims of internal experiments at the Unit, and that he himself vivisected thousands.

According to A. S. Wells, the majority of victims were Chinese with a lesser percentage being Russian, Mongolian, and Korean. They may also have included a small number of European, American, Indian, Australian and New Zealander prisoners of war. One member of the Japanese Youth Corp, also known as the Yokusan Sonendan, who worked for Unit 731, stated that not only were Chinese, Russians, and Koreans present, but also Americans, British, and Frenchmen. Sheldon H. Harris documented that the victims were generally political dissidents, communist sympathizers, ordinary criminals, impoverished civilians, and the mentally handicapped. Author Seiichi Morimura estimates that almost 70% of the victims who died in the Pingfang camp were Chinese (including both military and civilian), while close to 30% of the victims were Russian.

Imprisoned as a POW at the Mukden camp (housing American, British, Australian and New Zealand soldiers), which was not part of Unit 731, Robert Peaty (1903–1989), a Major in the Royal Army Ordnance Corps, was the senior ranking allied officer. During his captivity, he kept a secret diary. He was interviewed by the Imperial War Museum in 1981, and the audio recording tape reels are in the IWM's archives. Peaty recounts: "I was reminded of Dante’s Inferno – abandon hope all ye who enter here ...." His diary recorded the regular injections of infectious diseases that were disguised as preventative vaccinations. His entry for January 30, 1943 notes: "Everyone received a 5 cc Typhoid-paratyphoid A inoculation." The February 23, 1943 entry read: "Funeral service for 142 dead. 186 have died in 5 days, all Americans."

A sketch of the prison cells, done by a member of Unit 731. The octagonal sketch represents the pressure chamber.

No one who entered Unit 731 came out alive. Prisoners were usually received into Unit 731 at night in motor vehicles painted black with a ventilation hole but no windows. The vehicle would pull up at the main gates and one of the drivers would go to the guardroom and report to the guard. That guard would then telephone to the "Special Team" in the inner-prison (Shiro Ishii's brother was head of this Special Team). Then, the prisoners would be transported through a secret tunnel dug under the facade of the central building to the inner-prisons. One of the prisons housed women and children (Building 8), while the other prison housed men (Building 7). Once at the inner-prison, technicians would take samples of the prisoners' blood and stool, test their kidney function and collect other physical data. Once deemed healthy and fit for experimentation, prisoners lost their names and were given a three digit number which they retained until their death. Whenever prisoners died after the experiments they had been subjected to, a clerk of the 1st Division struck their numbers off an index card and took the deceased prisoner's manacles to be put on new arrivals to the prison.

There is at least one recorded instance of "friendly" social interaction between prisoners and Unit 731 staff. Technician Naokata Ishibashi interacted with two female prisoners. One prisoner was a 21 year old Chinese woman, the other a Soviet girl who was 19 years of age. Ishibashi asked where she came from and learned that she was from Ukraine. The two prisoners told Ishibashi that they had not seen their faces in a mirror since being captured, and begged him to get one. Ishibashi sneaked a mirror to them through a hole in the cell door. Prisoners were repeatedly re-used for experiments as long as they were healthy enough. The average life expectancy of a prisoner once they had entered the Unit was 2 months. Some prisoners were alive in the Unit for over 12 months, and many female prisoners gave birth in the Unit.

The prison cells had wooden floors and a squat toilet in each. There was space between the outer walls of the cells and the outer walls of the prison, enabling the guards to walk behind the cells. Each cell door had a small window in it. Chief of the Personnel Division of the Kwantung Army Headquarters Tamura Tadashi testified that when he was shown the inner-prison, he looked into the cells and saw living people in chains, some moved around, others were lying on the bare floor and were in a very sick and helpless condition. Former Unit 731 Youth Corps member Yoshio Shinozuka testified that the windows in these prison doors were so small that it was difficult to see in. The inner-prison was a highly secured building complete with cast-iron doors. No one could enter without special permits and an ID pass with a photograph, and the entry/exit times were recorded. The "special team" worked in these two inner-prison buildings. This team wore white overall suits, army hats, rubber boots, and pistols strapped to their sides.

A former member of the Special Team (who insisted on anonymity) recalled in 1995 his first vivisection conducted at the Unit:

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Other sources suggest that it was the usual practice in the Unit for surgeons to stuff a rag (or medical gauze) into the mouth of prisoners before commencing vivisection, in order to stifle any screaming.

Despite the prison's status as a highly secure building, at least one unsuccessful escape attempt did occur. Corporal Kikuchi Norimitsu testified that he was told by another unit member that a prisoner "had shown violence and had struck the experimenter with a door handle" and then "jumped out of the cell and ran down the corridor, seized the keys and opened the iron doors and some of the cells. Some of the prisoners managed to jump out but these were only the bold ones. These bold ones were shot". Seiichi Morimura in his book "The Devil's Feast" went into some greater detail regarding this escape attempt. Two Russian male prisoners were in a cell with handcuffs on, one of them lay flat on the floor pretending to be sick. This got the attention of a staff member who saw it as an unusual condition. That staff member decided to enter the cell. The Russian lying on the floor suddenly sprang up and knocked the guard down. The two Russians opened their handcuffs, took the keys and opened some other cells while yelling. Some prisoners, including Russian and Chinese, were frantically roaming the corridors and kept yelling and shouting. One Russian shouted to the members of Unit 731, demanding to be shot rather than used as an experimental object. This Russian was shot to death. One staff member who was an eyewitness at this escape attempt recalled: "spiritually we were all lost in front of the 'marutas' who had no freedom and no weapons. At that time we understood in our hearts that justice was not on our side". Unfortunately for the prisoners of Unit 731, escape was an impossibility. Even if they had managed to escape the quadrangle (itself a heavily fortified building full of staff), they would have had to get over a 3 meter high brick wall surrounding the complex, and then across a dry moat filled with electrified wire running around the perimeter of the complex (able to be seen in aerial pictures of the Unit).

Interestingly, simply being Japanese was no protection from potentially becoming a victim of the Unit and subjected to vivisection just like the prisoners. Yoshio Tamura, an assistant in the Special Team, recalled that Yoshio Sudō, an employee of the first division at Unit 731, became infected with bubonic plague as a result of the production of plague bacteria. The Special Team was then ordered to vivisect Sudō. Tamura recalled:

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Additionally, Unit 731 Youth Corps member Yoshio Shinozuka testified that his friend junior assistant Mitsuo Hirakawa was vivisected as a result of being accidentally infected with plague.

Known unit members

In April 2018, the National Archives of Japan disclosed a nearly complete list of 3,607 members of Unit 731 to Katsuo Nishiyama, a professor at Shiga University of Medical Science. Nishiyama reportedly intends to publish the list online to encourage further study into the unit.

Previously disclosed members include:

Shirō Ishii, commander of Unit 731

Ryōichi Naitō

File:Yoshimura Hisato.jpg

Yoshimura Hisato

• Lieutenant General Shirō Ishii
• Lieutenant Colonel Ryoichi Naito, founder of the pharmaceutical company Green Cross
• Professor, Major General Masaji Kitano, commander, 1942–1945^:137
• Yoshio Shinozuka
• Yasuji Kaneko
• Kazuhisa Kanazawa, chief of the 1st Division of Branch 673 of Unit 731
• Ryoichiro Hotta, member of the Hailar Branch of Unit 731
• Shigeo Ozeki, civilian employee^:243
• Kioyashi Mineoi, civilian employee^:243
• Masateru Saito, civilian employee^:243
• Major General Hitoshi Kikuchi, head of Research Division, 1942–1945^:133
• Lieutenant General [unknown first name] Yasazaka, doctor^:241
• Yoshio Furuichi, student at Sunyu Branch of Unit 731^:243

There were also twelve members who were formally tried and sentenced in the Khabarovsk War Crime Trials.

Other suspected Japanese war criminals who were never indicted include three postwar prime ministers: Hatoyama Ichirō (1954–1956), Ikeda Hayato (1960–1964), and Kishi Nobusuke (1957).

Unit 731 members sentenced in the Khabarovsk War Crime Trials

Name	Military position	Unit position:5	Unit	Sentenced years in labor camp:534–535
Kiyoshi Shimizu	Lieutenant colonel	Chief of General Division, 1939–1941, Head of Production Division, 1941–1945:131	731	25
Otozō Yamada	General	Direct controller, 1944–1945:232	731, 100	25
Ryuji Kajitsuka	Lieutenant general of the Medical Service	Chief of the Medical Administration:131	731	25
Takaatsu Takahashi	Lieutenant general of the Veterinary Service	Chief of the Veterinary Service	731	25
Tomio Karasawa	Major of the Medical Service	Chief of a section	731	20
Toshihide Nishi	Lieutenant colonel of the Medical Service	Chief of a division	731	18
Masao Onoue	Major of the Medical Service	Chief of a branch	731	12
Zensaku Hirazakura	Lieutenant	Officer	100	10
Kazuo Mitomo	Senior sergeant	Member	731	15
Norimitsu Kikuchi	Corporal	Probationer medical orderly	Branch 643	2
Yuji Kurushima	[none]	Laboratory orderly	Branch 162	3
Shunji Sato	Major general of the Medical Service	Chief of the Medical Service:192	731, 1644	20

Divisions

Unit 731 was divided into eight divisions:

• Division 1: research on bubonic plague, cholera, anthrax, typhoid and tuberculosis using live human subjects; for this purpose, a prison was constructed to contain around three to four hundred people
• Division 2: research for biological weapons used in the field, in particular the production of devices to spread germs and parasites
• Division 3: production of shells containing biological agents; stationed in Harbin
• Division 4: bacteria mass-production and storage
• Division 5: training of personnel
• Divisions 6–8: equipment, medical and administrative units

Facilities

The Harbin bioweapon facility is open to visitors

Information sign at the site today

Unit 731 had other units underneath it in the chain of command; there were several other units under the auspice of Japan's biological weapons programs. Most or all Units had branch offices, which were also often referred to as "Units". The term Unit 731 can refer to the Harbin complex itself, or it can refer to the organization and its branches, sub-Units and their branches.

The Unit 731 complex covered 6 square kilometers (2.3 sq mi) and consisted of more than 150 buildings. The design of the facilities made them hard to destroy by bombing. The complex contained various factories. It had around 4,500 containers to be used to raise fleas, six cauldrons to produce various chemicals, and around 1,800 containers to produce biological agents. Approximately 30 kilograms (66 lb) of bubonic plague bacteria could be produced in a few days.

Some of Unit 731's satellite (branch) facilities are still in use by various Chinese industrial companies. A portion has been preserved and is open to visitors as a War Crimes Museum.

Branches

Unit 731 had branches in Linkou (Branch 162), Mudanjiang, Hailin (Branch 643), Sunwu (Branch 673), Toan and Hailar (Branch 543).^{:60, 84, 124, 310}

Tokyo

A medical school and research facility belonging to Unit 731 operated in the Shinjuku District of Tokyo during World War II. In 2006, Toyo Ishii—a nurse who worked at the school during the war—revealed that she had helped bury bodies and pieces of bodies on the school's grounds shortly after Japan's surrender in 1945. In response, in February 2011 the Ministry of Health began to excavate the site.

While Tokyo courts acknowledged in 2002 that Unit 731 had been involved in biological warfare research, as of 2011 the Japanese government had made no official acknowledgment of the atrocities committed against test subjects, and rejected the Chinese government's requests for DNA samples to identify human remains (including skulls and bones) found near an army medical school.

At Tokyo's Kyushu Imperial University in 1945 US POWs from a shot down B-29 were subjected to fatal medical experimentation.

Surrender and immunity

Operations and experiments continued until the end of the war. Ishii had wanted to use biological weapons in the Pacific War since May 1944, but his attempts were repeatedly snubbed.

Destruction of evidence

With the coming of the Red Army in August 1945, the unit had to abandon their work in haste. Ministries in Tokyo ordered the destruction of all incriminating materials, including those in Pingfang. Potential witnesses, such as the 300 remaining prisoners were either gassed or fed poison while the 600 Chinese and Manchurian laborers were shot. Ishii ordered every member of the group to disappear and "take the secret to the grave". Potassium cyanide vials were issued for use in case the remaining personnel were captured.

Skeleton crews of Ishii's Japanese troops blew up the compound in the final days of the war to destroy evidence of their activities, but many were sturdy enough to remain somewhat intact.

A photograph of the Unit 731 square building taken during its destruction in 1945

American grant of immunity

Among the individuals in Japan after its 1945 surrender was Lieutenant Colonel Murray Sanders, who arrived in Yokohama via the American ship Sturgess in September 1945. Sanders was a highly regarded microbiologist and a member of America's military center for biological weapons. Sanders' duty was to investigate Japanese biological warfare activity. At the time of his arrival in Japan he had no knowledge of what Unit 731 was. Until Sanders finally threatened the Japanese with bringing the Soviets into the picture, little information about biological warfare was being shared with the Americans. The Japanese wanted to avoid prosecution under the Soviet legal system, so the next morning after he made his threat, Sanders received a manuscript describing Japan's involvement in biological warfare. Sanders took this information to General Douglas MacArthur, who was the Supreme Commander of the Allied Powers responsible for rebuilding Japan during the Allied occupations. MacArthur struck a deal with Japanese informants: He secretly granted immunity to the physicians of Unit 731, including their leader, in exchange for providing America, but not the other wartime allies, with their research on biological warfare and data from human experimentation. American occupation authorities monitored the activities of former unit members, including reading and censoring their mail. The Americans believed that the research data was valuable, and did not want other nations, particularly the Soviet Union, to acquire data on biological weapons.

The Tokyo War Crimes Tribunal heard only one reference to Japanese experiments with "poisonous serums" on Chinese civilians. This took place in August 1946 and was instigated by David Sutton, assistant to the Chinese prosecutor. The Japanese defense counsel argued that the claim was vague and uncorroborated and it was dismissed by the tribunal president, Sir William Webb, for lack of evidence. The subject was not pursued further by Sutton, who was probably unaware of Unit 731's activities. His reference to it at the trial is believed to have been accidental.

Separate Soviet trials

Although publicly silent on the issue at the Tokyo Trials, the Soviet Union pursued the case and prosecuted twelve top military leaders and scientists from Unit 731 and its affiliated biological-war prisons Unit 1644 in Nanjing, and Unit 100 in Changchun, in the Khabarovsk War Crime Trials. Included among those prosecuted for war crimes, including germ warfare, was General Otozō Yamada, the commander-in-chief of the million-man Kwantung Army occupying Manchuria.

The trial of those captured Japanese perpetrators was held in Khabarovsk in December 1949. A lengthy partial transcript of the trial proceedings was published in different languages the following year by a Moscow foreign languages press, including an English-language edition. The lead prosecuting attorney at the Khabarovsk trial was Lev Smirnov, who had been one of the top Soviet prosecutors at the Nuremberg Trials. The Japanese doctors and army commanders who had perpetrated the Unit 731 experiments received sentences from the Khabarovsk court ranging from two to 25 years in a Siberian labor camp. The United States refused to acknowledge the trials, branding them communist propaganda. The sentences doled out to the Japanese perpetrators were unusually lenient by Soviet standards, and all but one of the defendants returned to Japan by the 1950s (with the remaining prisoner committing suicide inside his cell). In addition to the accusations of propaganda, the US also asserted that the trials were to only serve as a distraction from the Soviet treatment of several hundred thousand Japanese prisoners of war; meanwhile, the USSR asserted that the US had given the Japanese diplomatic leniency in exchange for information regarding their human experimentation. The accusations of both the US and the USSR were true, and it is believed that the Japanese had also given information to the Soviets regarding their biological experimentation for judicial leniency. This was evidenced by the Soviet Union building a biological weapons facility in Sverdlovsk using documentation captured from Unit 731 in Manchuria.

Official silence under United States occupation

As above, under the American occupation the members of Unit 731 and other experimental units were allowed to go free. On 6 May 1947, Douglas MacArthur, as Supreme Commander of the Allied Forces, wrote to Washington that "additional data, possibly some statements from Ishii, can probably be obtained by informing Japanese involved that information will be retained in intelligence channels and will not be employed as 'war crimes' evidence".

One graduate of Unit 1644, Masami Kitaoka, continued to do experiments on unwilling Japanese subjects from 1947 to 1956 while working for Japan's National Institute of Health Sciences. He infected prisoners with rickettsia and mental health patients with typhus. Shiro Ishii, as the chief of the unit, was granted war crime immunity from the US occupation authorities, because of his provision of human experimentation research materials to the US. From 1948 to 1958, less than 5% of the documents were transferred onto microfilm and stored in the National Archives of the United States, before being shipped back to Japan.

Post-occupation Japanese media coverage and debate

Japanese discussions of Unit 731's activity began in the 1950s, after the end of the American occupation of Japan. In 1952, human experiments carried out in Nagoya City Pediatric Hospital, which resulted in one death, were publicly tied to former members of Unit 731. Later in that decade, journalists suspected that the murders attributed by the government to Sadamichi Hirasawa were actually carried out by members of Unit 731. In 1958, Japanese author Shūsaku Endō published the book The Sea and Poison about human experimentation, which is thought to have been based on a real incident.

The author Seiichi Morimura published The Devil's Gluttony (悪魔の飽食) in 1981, followed by The Devil's Gluttony: A Sequel in 1983. These books purported to reveal the "true" operations of Unit 731, but falsely attributed unrelated photos to the Unit, which raised questions about their accuracy.

Also in 1981 appeared the first direct testimony of human vivisection in China, by Ken Yuasa. Since then many more in-depth testimonies have appeared in Japanese. The 2001 documentary Japanese Devils was composed largely of interviews with 14 members of Unit 731 who had been taken as prisoners by China and later released.

Significance in postwar research of bio-warfare and medicine

There was consensus among US researchers in the postwar period that the human experimentation data gained was of little value to the development of American biological weapons and medicine. Postwar reports have generally regarded the data as "crude and ineffective", with one expert even deeming it "amateurish". Harris speculates that the reason US scientists generally wanted to acquire it was due to the concept of forbidden fruit, believing that lawful and ethical prohibitions could affect the outcomes of their research.

Official government response in Japan

Unit 731 presents a special problem, since unlike Nazi human experimentation, which the United States publicly condemned, the activities of Unit 731 are known to the general public only from the testimonies of willing former unit members, and testimony cannot be employed to determine indemnity in this way.^{[citation needed]}

Japanese history textbooks usually contain references to Unit 731, but do not go into detail about allegations, in accordance with this principle. Saburō Ienaga's New History of Japan included a detailed description, based on officers' testimony. The Ministry for Education attempted to remove this passage from his textbook before it was taught in public schools, on the basis that the testimony was insufficient. The Supreme Court of Japan ruled in 1997 that the testimony was indeed sufficient and that requiring it to be removed was an illegal violation of freedom of speech.

In 1997, the international lawyer Kōnen Tsuchiya filed a class action suit against the Japanese government, demanding reparations for the actions of Unit 731, using evidence filed by Professor Makoto Ueda of Rikkyo University. All Japanese court levels found that the suit was baseless. No findings of fact were made about the existence of human experimentation, but the decision of the court was that reparations are determined by international treaties and not by national court cases.^{[citation needed]}

In August 2002, the Tokyo district court ruled for the first time that Japan had engaged in biological warfare. Presiding judge Koji Iwata ruled that Unit 731, on the orders of the Imperial Japanese Army headquarters, used bacteriological weapons on Chinese civilians between 1940 and 1942, spreading diseases including plague and typhoid in the cities of Quzhou, Ningbo, and Changde. However, he rejected the victims' claims for compensation on the grounds that they had already been settled by international peace treaties.

In October 2003, a member of the House of Representatives of Japan filed an inquiry. Prime Minister Junichiro Koizumi responded that the Japanese government did not then possess any records related to Unit 731, but the government recognized the gravity of the matter and would publicize any records that were located in the future. In April 2018, the National Archives of Japan released the names of 3,607 members of Unit 731, in response to a request by Professor Katsuo Nishiyama of the Shiga University of Medical Science.

Abroad

After WWII, the Office of Special Investigations created a watchlist of suspected Axis collaborators and persecutors who are banned from entering the United States. While they have added over 60,000 names to the watchlist, they have only been able to identify under 100 Japanese participants. In a 1998 correspondence letter between the DOJ and Rabbi Abraham Cooper, Eli Rosenbaum, director of OSI, stated that this was due to two factors. (1) While most documents captured by the US in Europe were microfilmed before being returned to their respective governments, the Department of Defense decided to not microfilm its vast collection of documents before returning them to the Japanese government. (2) The Japanese government has also failed to grant the OSI meaningful access to these and related records after the war, while European countries, on the other hand, have been largely cooperative, the cumulative effect of which is that information pertaining to identifying these individuals is, in effect, impossible to recover.

See also

• Belmont Report
• Common Rule
• Declaration of Helsinki
• Doctors' Trial
• Human subject research
• Informed consent
• Nazi human experimentation
• Nuremberg Code

References

ISBN links support NWE through referral fees

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Further reading

• Barenblatt, Daniel. A Plague Upon Humanity: The Secret Genocide of Axis Japan's Germ Warfare Operation, HarperCollins, 2004. Template:ISBN.
• Barnaby, Wendy. The Plague Makers: The Secret World of Biological Warfare, Frog Ltd, 1999. Template:ISBN, Template:ISBN, Template:ISBN, Template:ISBN.
• Cook, Haruko Taya; Cook, Theodore F. Japan at war: an oral history, New York: New Press: Distributed by Norton, 1992. Template:ISBN. Cf. Part 2, Chapter 6 on Unit 731 and Tamura Yoshio.
• Endicott, Stephen and Hagerman, Edward. The United States and Biological Warfare: Secrets from the Early Cold War and Korea, Indiana University Press, 1999. Template:ISBN.
• Felton, Mark. The devil's doctors: Japanese Human Experiments on Allied Prisoners of War, Pen & Sword, 2012. Template:ISBN
• Gold, Hal. Unit 731 Testimony, Charles E Tuttle Co., 1996. Template:ISBN.
• Grunden, Walter E., Secret Weapons & World War II: Japan in the Shadow of Big Science, University Press of Kansas, 2005. Template:ISBN.
• Handelman, Stephen and Alibek, Ken. Biohazard: The Chilling True Story of the Largest Covert Biological Weapons Program in the World – Told from Inside by the Man Who Ran It, Random House, 1999. Template:ISBN, Template:ISBN.
• Harris, Robert and Paxman, Jeremy. A Higher Form of Killing: The Secret History of Chemical and Biological Warfare, Random House, 2002. Template:ISBN.
• Harris, Sheldon H. Factories of Death: Japanese Biological Warfare 1932–45 and the American Cover-Up, Routledge, 1994. Template:ISBN, Template:ISBN.
• Lupis, Marco. "Orrori e misteri dell'Unità 731: la 'fabbrica' dei batteri killer", La Repubblica, 14 aprile 2003,
• Mangold, Tom; Goldberg, Jeff, Plague wars: a true story of biological warfare, Macmillan, 2000. Cf. Chapter 3, Unit 731.
• Moreno, Jonathan D. Undue Risk: Secret State Experiments on Humans, Routledge, 2001. Template:ISBN.
• Nie, Jing Bao, et al. Japan's Wartime Medical Atrocities: Comparative Inquiries in Science, History, and Ethics (2011) excerpt and text search
• Williams, Peter. Unit 731: Japan's Secret Biological Warfare in World War II, Free Press, 1989. Template:ISBN.

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