Unit 731 - WikiHQ

, officially known as the Manchu Detachment 731 and also referred to as the Kamo Detachment was a secret research facility operated by the Imperial Japanese Army between 1933 and 1945. It was located in the Pingfang district of Harbin, in the Japanese puppet state of Manchukuo (now part of Northeast China), and maintained multiple branches across mainland China and Southeast Asia.

Unit 731 was responsible for large-scale biological and chemical warfare research, as well as lethal human experimentation. The facility was led by General Shirō Ishii and received strong support from the Japanese military. Its activities included infecting prisoners with deadly diseases, conducting vivisection, performing organ harvesting, testing hypobaric chambers, amputating limbs, and exposing victims to chemical agents and explosives. Prisoners—often referred to as "logs" by the staff—were mainly Chinese civilians, but also included Russians, Koreans, and others, including children and pregnant women. No documented survivors are known.

An estimated 14,000 people were killed inside the facility itself. In addition, biological weapons developed by Unit 731 caused the deaths of between 200,000 people in Chinese cities and villages, through deliberate contamination of water supplies, food, and agricultural land.

On 28 August 2002, the Tokyo District Court formally acknowledged that Japan had conducted biological warfare in China and held the state responsible for related deaths.

Formations

thumb|Building of the Unit 731 bioweapon facility in [[Harbin]]

The Empire of Japan initiated its biological weapons program during the 1930s, due to the prohibition of biological weapons in interstate conflicts by the Geneva Protocol of 1925. They reasoned that the ban implied their efficacy as weapons. Japan decided to build Unit 731 in Manchuria because the occupation not only gave the Japanese an advantage of separating the research station from their island but also gave them access to as many Chinese individuals as they wanted for use as test subjects. The research and experimentation rooms were constructed around the detention area, allowing researchers to conduct their daily work while monitoring the prisoners.

Unit 731 was a clandestine division of the Japanese Kwantung Army based in Manchuria during World War II. Led by Lieutenant General Shirō Ishii, the organization dedicated to the advancement of biological weaponry within the imperial army was commonly referred to as the Ishii Network. The Ishii Network was headquartered at the Epidemic Prevention Research Laboratory, established in 1932 at the Japanese Army Military Medical School in Tokyo. Unit 731 was the first of several covert units established as offshoots of the research lab, serving as field stations and experimental sites to advance biological warfare techniques. These efforts culminated in the experimental deployment of biological weapons on Chinese cities, a direct breach of the 1925 Geneva Protocol prohibiting the use of biological and chemical weapons in warfare. Participants in these activities were aware of the violations and recognized the inhumanity of using human subjects in laboratory experiments, prompting the establishment of Unit 731 and other secret units. It was divided at that time into the "Ishii Unit" and the "Wakamatsu Unit", with a base in Xinjing. From August 1940 on, the units were known collectively as the "Epidemic Prevention and Water Purification Department of the Kwantung Army" or "Unit 731" for short.

One of Ishii's main supporters inside the army was Colonel Chikahiko Koizumi, who later served as 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 6,000 deaths and 15,000 wounded as a result of the chemical attack.

Zhongma Fortress

Unit Tōgō was set into motion in the Zhongma Fortress, a prison and experimentation camp in Beiyinhe, a village south of Harbin on the South Manchuria Railway. The prisoners brought to Zhongma included common criminals, captured bandits, and anti-Japanese partisans, as well as political prisoners and people rounded up on false charges by the Kempeitai. Prisoners were generally well fed on a diet of rice or wheat, meat, fish, and occasionally even alcohol, in order to be in normal health at the beginning of experiments. Then, 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. A prison break in the autumn of 1934, which jeopardized the facility's secrecy, and an explosion in 1935, which was believed to be sabotage, led Ishii to shut down the Zhongma Fortress. He then received authorization to relocate to Pingfang, approximately south of Harbin, to establish a new, much larger facility.

thumb|Close-up photo of the Unit 731 main "square building" taken by Unit 731's aviation and photography class in 1940

Other units

In addition to the establishment of Unit 731, the decree also called for the creation 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, Malaya (present-day Malaysia), Indonesia, the Philippines, Papua New Guinea, Thailand, and Burma. All of these units comprised Ishii's network, which, at its height in 1939, oversaw over 10,000 personnel. Medical doctors and professors from Japan were enticed to join Unit 731 both by the rare opportunity to conduct human experimentation and the Army's strong financial backing.

Experiments

The military police and the Special Services Agency were responsible for locating victims to serve as test subjects for the unit, while a group of physicians was tasked with maintaining the health of the victims and dispatching them for experimentation.

According to American historian Sheldon H. Harris:

<blockquote>The Togo Unit employed gruesome tactics to secure specimens of select body organs. If Ishii or one of his co-workers wished to do research on the human brain, then they would order the guards to find them a useful sample. A prisoner would be taken from his cell. Guards would hold him while another guard would smash the victim's head open with an axe. His brain would be extracted off to the pathologist, and then to the crematorium for the usual disposal.</blockquote>

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

<blockquote>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.</blockquote>

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. A special project, codenamed Maruta, used human beings for experiments. Test subjects were gathered from the surrounding population and sometimes euphemistically referred to as , as in "How many logs fell?" This term originated as a staff joke because the official cover story for the facility, given to local authorities, was that it was a lumber mill. According to a junior uniformed civilian employee of the Imperial Japanese Army working in Unit 731, the project was internally called "Holzklotz", from the German word for log. The corpses of "sacrificed" subjects were disposed of by incineration.

At the age of 14, on the encouragement of a former school teacher, Hideo Shimizu joined the fourth group of minors assigned to Unit 731. He recalled that he was brought to a specimen room where jars of various heights, with some reaching the height of an adult, were stored. In a video interview, former Unit 731 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.

Prisoners had limbs amputated in order to study blood loss. Limbs removed were sometimes reattached to the opposite side of the victims' bodies. Some prisoners had their stomachs surgically removed and their esophagus reattached to the intestines. Parts of organs, such as the brain, lungs, and liver, were removed from others. Yuasa said that when he performed vivisections on captives, they were "all for practice rather than for research", and that such practices were "routine" among Japanese doctors stationed in China during the war.

Biological warfare

thumb|Ruins of a boiler building at the Unit 731 [[bioweapons facility]]

Unit 731 and its affiliated units (Unit 1644 and Unit 100, among others) were involved in research, development and experimental deployment of epidemic-creating biological weapons in assaults against the Chinese populace (both military and civilian) throughout World War II.

The Library of Congress holds three declassified documents from Unit 731, each more than 100 pages long, translated from Japanese into English. These documents provided comprehensive clinical records about the daily progression of various pathogens within the bodies of helpless prisoners who were experimented on by Japanese doctors.

Japanese soldiers provided testimony indicating that the research program had the capability to manufacture substantial quantities of biological agents on a monthly basis: 300 kg of plague, 500–700 kg of anthrax, 800–900 kg of typhoid, and 1,000 kg of cholera. Despite the significant production volumes, even small amounts of these bacteria could cause severe harm or death.

Ishii determined that fleas were efficient carriers of the plague, leading Unit 731 to focus on breeding large numbers of fleas. To achieve this goal, Unit 731 had approximately 4500 flea incubators, each capable of producing at least 45 kg of fleas per cycle. The substantial quantities of plague bacteria and fleas generated, combined with the severe illness and death rates associated with plague infection, illustrate the formidable biological warfare production capabilities wielded by the Japanese. Japanese researchers had the necessary materials to apply the scientific method to conduct experiments involving inoculation and the creation of airborne bacterial bombs. 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- and plague-carrier fleas, typhoid, 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 candy were given to unsuspecting victims. 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 biowarfare 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-infected 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.

In December 1944, the Japanese Navy explored the possibility of attacking cities in California with biological weapons, known as Operation PX or Operation Cherry Blossoms at Night. The plan for the attack involved Seiran aircraft launched by Sentoku submarine aircraft carriers upon the West Coast of the United States—specifically, the cities of San Diego, Los Angeles, and San Francisco. The planes would spread weaponized bubonic plague, cholera, typhus, dengue fever, and other pathogens in a biological terror attack upon the population. The submarine crews would infect themselves and run ashore in a suicide mission.

Weapons testing

Human targets were used to test grenades at various distances and 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.

Frostbite testing

thumb|Scan of [[Yoshimura Hisato's frostbite research data]]

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".

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 Japanese Journal of Physiology in 1950 in which he admitted to using 20 children and a three-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 Shimbun.

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.

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 victims shows: