Unit 731 It was officially known as the . Originally set up under the " Kempeitai " military police of the Empire of Japan , Unit 731 was taken over and commanded until the end of the war by General Shiro Ishii , an officer in the Kwantung Army . Between 3 , 000 and 12 , 000 men , women , and children — from which around 600 every year were provided by the " Kempeitai " — died during the human experimentation conducted by Unit 731 at the camp based in Pingfang alone , which does not include victims from other medical experimentation sites . Almost 70 % of the victims who died in the Pingfang camp were Chinese , including both civilian and military . Close to 30 % of the victims were Russian . Some others were South East Asians and Pacific Islanders , at the time colonies of the Empire of Japan , and a small number of the prisoners of war from the Allies of World War II ( although many more Allied POWs were victims of Unit 731 at other sites ) . Many of the scientists involved in Unit 731 went on to prominent careers in post - war politics , academia , business , and medicine . Some were arrested by Soviet forces and tried at the Khabarovsk War Crime Trials ; others surrendered to the American Forces . It has been postulated that one reason the scientists were not tried was that the information and experience gained in the studies of the biological warfare was of a great value for the United States biological weapons development program . On 6 May 1947 , Douglas MacArthur , as Supreme Commander of the Allied Forces , wrote to Washington 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 . " The deal concluded in 1948 . Formation . In 1932 , General Shirō Ishii ( 石井四郎 " Ishii Shirō " ) , chief medical officer of the Japanese Army and protégé of Army Minister Sadao Araki was placed in command of the Army Epidemic Prevention Research Laboratory . Ishii organized a secret research group , the " Tōgō Unit " , for various 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 Japanese army officers were impressed by the successful German use of chlorine gas at the second battle of Ypres , where the Allies suffered 15 , 000 casualties as a result of the chemical attack . Unit Tōgō was implemented in the Zhongma Fortress , a prison / experimentation camp in Beiyinhe , a village south of Harbin on the South Manchurian Railway . A jailbreak in autumn 1934 and later explosion ( believed to be an attack ) in 1935 led Ishii to shut down Zhongma Fortress . He received the authorization to move to Pingfang , approximately south of Harbin , to set up a new and much larger facility . In 1936 , Hirohito authorized , by imperial decree , the expansion of this unit and its integration into the Kwantung Army as the Epidemic Prevention Department . It was divided at the same time into the " Ishii Unit " and " Wakamatsu Unit " with a base in Hsinking . From August 1940 , all these 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 . Activities . A special project code - named " Maruta " used human beings for experiments . Test subjects were gathered from the surrounding population and were sometimes referred to euphemistically as 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 . In an account by a man who worked as a " junior uniformed civilian employee " of the Japanese Army in Unit 731 , the term " Maruta " came from German , meaning medical experiment , used in such contexts as , " How many logs fell ? " The test subjects were selected to give a wide cross - section of the population and included common criminals , captured bandits and anti - Japanese partisans , political prisoners , and also people rounded up by the " Kempeitai " for alleged " suspicious activities " . They included infants , the elderly , and pregnant women . Vivisection . Prisoners of war were subjected to vivisection without anesthesia . Vivisections were performed on prisoners after infecting them with various diseases . Scientists performed invasive surgery on prisoners , removing organs to study the effects of disease on the human body . These were conducted while the patients were alive because it was feared that the decomposition process would affect the results . The infected and vivisected prisoners included men , women , children , and infants . 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 ' limb s were frozen and amputated , while others had limbs frozen then thawed to study the effects of the resultant untreated gangrene and rotting . Some prisoners had their stomach s surgically removed and the esophagus reattached to the intestines . Parts of the brain , lungs , liver , etc . were removed from some prisoners . In 2007 , the Japanese army surgeon Ken Yuasa testified to the " Japan Times " that , " I was afraid during my first vivisection , but the second time around , it was much easier . By the third time , I was willing to do it . " He believes at least 1 , 000 people , including surgeons , were involved in vivisections over mainland China . Germ warfare attacks . Prisoners were injected with inoculations of disease , disguised as vaccinations , to study their effects . To study the effects of untreated venereal disease s , male and female prisoners were deliberately infected , often by rape , with syphilis and gonorrhea , then studied . 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 around and possibly more than 400 , 000 Chinese civilians . Tularemia was tested on Chinese civilians . 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 civilian and military ) throughout World War II . Plague - infested fleas , bred in the laboratories of Unit 731 and Unit 1644 , were spread by low - flying airplanes upon Chinese cities , coastal Ningbo in 1940 , and Changde , Hunan Province , in 1941 . This military aerial spraying killed thousands of people with bubonic plague epidemics . Weapons testing . Human targets were used to test grenade s positioned at various distances and in different positions . Flame thrower s were tested on humans . Humans were tied to stakes and used as targets to test germ - releasing bombs , chemical weapons , and explosive bomb s . Other experiments . In other tests , subjects were deprived of food and water to determine the length of time until death ; placed into high - pressure chambers until death ; experimented upon to determine the relationship between temperature , burns , and human survival ; placed into centrifuge s 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 to determine if it could be a substitute for saline ; and burned or prematurely buried alive . Biological warfare . Japanese scientists performed tests on prisoners with 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 the bubonic plague . Some of these bombs were designed with ceramic ( porcelain ) shells , an idea proposed by Ishii in 1938 . These bombs enabled Japanese soldiers to launch biological attacks , infecting agriculture , reservoirs , wells , and other areas with anthrax , plague - carrier fleas , typhoid , dysentery , cholera , and other deadly pathogens . During biological bomb experiments , scientists 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 out to unsuspecting victims , and the results examined . In 2002 , Changde , China , site of the flea spraying attack , held an " International Symposium on the Crimes of Bacteriological Warfare " which estimated that at least 580 , 000 people died as a result of the attack . The historian Sheldon Harris claims that 200 , 000 died . In addition to Chinese casualties , 1 , 700 Japanese in Chekiang were killed by their own biological weapons while attempting to unleash the biological agent , which indicates serious issues with distribution . Divisions . Unit 731 was divided into eight divisions : Facilities . The Unit 731 complex covered six square kilometers 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 flea s , six cauldrons to produce various chemicals , and around 1 , 800 containers to produce biological agents . Approximately 30 kg of bubonic plague bacteria could be produced in several days . Some of Unit 731 ' s satellite facilities are in use by various Chinese industrial concerns . A portion has been preserved and is open to visitors as a War Crimes Museum . 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 . China requested DNA samples from any human remains discovered at the site . The Japanese government — which has never officially acknowledged the existence of Unit 731 — rejected the request . Canton . The related Unit 8604 was operated by the Japanese Southern China Area Army and stationed at Canton ( Guangzhou ) . This installation conducted human experimentation in food and water deprivation as well as water - borne typhus . According to postwar testimony , this facility served as the main rat breeding farm for the medical units to provide them with bubonic plague vectors for experiments . Related units . Unit 731 was part of the Epidemic Prevention and Water Purification Department which dealt with contagious disease and water supply generally . Mukden POW camp . According to Maj . Robert Peaty , of the Royal Army Ordnance Corps , who was the senior British officer at Mukden , a prisoner - of - war camp 350 miles from Pingfan , doctors from Unit 731 administered the regular injections of infectious diseases , disguised as harmless vaccinations , which eventually killed 186 Americans . Surrender and immunity . Operations and experiments continued until the end of the war . Ishii had wanted to use biological weapons in the Pacific conflict since May 1944 , but his attempts were repeatedly snubbed . Destruction of evidence . With the Russian invasion of Manchukuo and Mengjiang in August 1945 , the unit had to abandon their work in haste . The members and their families fled to Japan . Ishii ordered every member of the group " to take the secret to the grave " , threatening to find them if they failed , and prohibiting any of them from going into public work back in Japan . Potassium cyanide vials were issued for use in the event that the remaining personnel were captured . Skeleton crew s of Ishii ' s Japanese troops blew the compound up in the final days of the war to destroy evidence of their activities , but most were so well constructed that they survived somewhat intact . American grant of immunity . After Imperial Japan surrendered to the Allies in 1945 , Douglas MacArthur became the Supreme Commander of the Allied Powers , rebuilding Japan during the Allied occupation . MacArthur 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 . American occupation authorities monitored the activities of former unit members , including reading and censoring their mail . The U . S . believed that the research data was valuable . The U . S . 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 counselor 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 likely 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 Americans refused to acknowledge the trials , branding them communist propaganda . After World War II , the Soviet Union built a biological weapons facility in Sverdlovsk using documentation captured from Unit 731 in Manchuria . After World War II . Official silence under Occupation . As above , under the American occupation the members of Unit 731 and other experimental units were allowed to go free . One graduate of Unit 1644 , Masami Kitaoka , continued to do experiments on unwilling Japanese subjects from 1947 to 1956 while working for the National Institute of Health Sciences . He infected prisoners with rickettsia and mental health patients with typhus . 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 Shusaku Endo published the book " The Sea and Poison " about human experimentation , which is thought to have been based on a real incident . The author Morimura Seiichi published the book " The Devil ' s Gluttony " ( 悪魔の飽食 ) in 1981 , followed by " The Devil ' s Gluttony : A Sequel " in 1983 . This purported to reveal the " true " operations of Unit 731 , but actually confused them with that of Unit 100 , and falsely used unrelated photos attributing them to Unit 731 , which raised questions about its 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 . Official government response in Japan . Since the end of the US Occupation , the Japanese government has repeatedly apologized for its prewar behavior in general , but specific apologies and indemnities are determined on the basis of bilateral determination that crimes occurred , which requires a high standard of evidence . Unit 731 presents a special problem , since unlike Nazi human experimentation which is extremely well documented , the activities of Unit 731 are known only from the testimonies of former unit members , and testimony cannot be employed to determine indemnity in this way . Japanese history textbooks usually contain references to Unit 731 , but do not go into detail about allegations , in accordance with this principle . Saburo 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 Rikkyo University professor Makoto Ueda . All 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 local court cases . In October 2003 , the Prime Minister of Japan responded to an inquiry from a member of the House of Representatives of Japan stating that , while the current Japanese government does not possess any records related to Unit 731 , they recognize the gravity of the matter and will publicize any records that are located in the future . Abroad . The Chinese film " Men Behind the Sun " , directed by Tun Fei Mou in 1988 , is a graphic film about the atrocities committed by Unit 731 , as is the Russian film " Philosophy of a Knife " , directed by Andrey Iskanov and released in 2008 . James T . Hong produced a 2007 documentary about Unit 731 told from the Chinese and Japanese sides called " 731 : Two Versions of Hell " . Bruce Dickinson ' s 1994 CD - single " Tears of the Dragon " contains a song entitled " The Breeding House " describing the atrocities committed by Unit 731 and the immunity granted by the Americans to the physicians of the Unit . American thrash metal band Slayer ' s 2009 album " World Painted Blood " contains a song entitled " Unit 731 " describing the events and atrocities that occurred at Unit 731 . " The X - Files " episode " 731 " was a reference to Unit 731 , in which former members secretly continue their experiments on humans under control of a covert U . S . government agency . " ReGenesis " episode " Let it burn " ( Season 3 , episode 9 ) mentions Unit 731 after it was discovered outbreaks of anthrax and glanders was from World War 2 Japan .