Why Japanese doctors performed human experiments in China 1933-1945

- Takashi Tsuchiya
Associate Professor, Department of Philosophy
Osaka City University, Osaka, Japan
Email: tsuchiya@lit.osaka-cu.ac.jp

Eubios Journal of Asian and International Bioethics 10 (2000), 179-180.
1. "Factories of Death"

From 1933 to 1945, Japanese doctors in China performed thousands of cruel experiments on Chinese, Russians, Mongolians, and Koreans and killed all of them. At Unit 731 alone, at least 3,000 people were tortured and murdered. In addition, similar human experiments and vivisections were done at four branches of Unit 731, four other "Boeki Kyusui Bu" (Anti-Epidemic Water Supply and Purification Bureaus), "Gunju Boeki Sho" (Anti-Epizootic Protection Units) including Unit 100, the Manchuria Medical School, and army hospitals (1). These experiments and vivisections can be classified under the following four categories.

(1) vivisections for training newly employed army surgeons

At army hospitals in China, army surgeons did many vivisections on Chinese prisoners. These doctors performed appendectomies and tracheostomies on the prisoners, shot them and took bullets from their bodies, cut their arms and legs and sewed up the skin around the wounds, and finally killed them. This surgical practice was purportedly part of the training program of newly employed army surgeons to teach them how to treat wounded soldiers at the front lines. However, since in these "training" careful skill to avoid the patients' needless harm and death was not required at all, the main purpose seems to have been to make surgeons desensitized, rather than to make themskillful.

(2) intentional infection of diseases

At the research faculties of the "Boeki Kyusui Bu," including Unit 731, researchers infected prisoners with many kinds of diseases, for example, plague, cholera, epidemic (kidney) hemorrhagic fever, tuberculosis, typhoid, tetanus, anthrax, glanders, typhus, and dysentery. The purpose of this intentional infection was to seek the pathogen of the disease (for example in the case of epidemic hemorrhagic fever), to measure the infectiousness of the pathogen, to select more infectious strains, to investigate the effect of bacteriological weapons, etc. The subjects were dissected after their death or vivisected to death.

(3) trials of nonstandardized treatments

Many prisoners were killed during trials of nonstandardized, unestablished, and unusual "treatments." Many kinds of vaccines in the development stage were tried directly on prisoners, with no prior trials on animals. As another example, searching for treatment for severe frostbite, Dr. Hisato Yoshimura made the prisoners' arms or legs suffer severe frostbite and then warmed them with hot water. When the temperature of the water was over 50 degrees centigrade, the skin and muscles came off. Some other doctors tried horse blood transfusion, which was said to be developed for emergency transfusion to wounded soldiers at the front lines where there is no blood supply.

(4) learning tolerance of the human body

There were deadly experiments with airtight chambers at Unit 731, the same ones as those conducted at the Nazi concentration camps. Some prisoners were forced to breathe poison gas. Others were killed by lowering the air pressure. In addition, there were doctors who only wanted to know how much air could be injected intravenously, how much bleeding brought prisoners to death, how many days prisoners could live with no food or water or only water without food, or how high electric current or voltage human beings could bear. There were also many trials of newly developed weapons with human subjects.

2. How Could the Massacre Be Possible?

But how could such a mass murder by human experimentation be possible? I think there are at least four explanations.

First, it cannot be denied that it was wartime, although Japan did not formally declare war against China. Since 1931, Japan invaded and militarily ruled parts of China. Japan's rule was known to be very cruel. Chinese people who were forced to work for the Japanese factories or suspected spies and resisters were treated violently or murdered routinely. The murders by human experiments were only one part of a huge massacre by the Japanese army. In addition, since victory in the war (especially over the United States and the United Kingdom) had become a supreme goal, Japanese people believed everything was justifiable if it was done for the sake of the country and "Tenno Heika" (the emperor).

Second, Japanese people at the time looked down upon people of other countries. Even now, as Japan is an isolated island country, there are only a few chances to communicate with foreigners. In addition, eugenic and racist ideologies were prevalent in Japan, as well as in western countries. Consequently, most Japanese then had prejudice against people in other Asian and European countries and discriminated against them. They thought Chinese, Korean, Mongolian, Russian, American, English, etc. were beings that need not be treated humanely, especially in wartime.

Moreover, the Japanese militarist government at the time feared communism. Therefore, persons who were suspected and arrested as spies of the USSR or communist resisters were tortured to death. This happened sometimes even in the Japanese homeland, but all the more and oftener in China.

Third, those who were arrested by the Kwantung Army Military Police as suspected spies or resisters were usually executed without trial. They were beings that must be killed. So researchers justified the murders by human experiments and vivisection with the excuse that it was better to utilize them for research and getting precious data than merely to execute them. This is the same rationale as that used by Nazi doctors who performed cruel experiments on prisoners in the concentration camps.

Fourth, since the human experimentation was performed strictly behind closed doors, researchers tended to lose a common sense of humanity. In preparing to make an excuse for it, they in fact recognized the inhumanity of their work. At any rate, leaders of the Japanese Army knew that if such barbarity had become widely known, the Japanese government would be severely condemned by international society. Therefore, experiments and vivisections with human subjects became "secrets of secrets." This made the laboratories completely hidden from the public, and researchers did not need to be worried about the constraints of medical ethics.

3. Couldn't the Doctors Avoid Participation?

The "factories of death" were run by army surgeons following Lt. Surgeon General Shiro Ishii. However, except at army hospitals, most of the doctors who performed human experiments and vivisections were academic researchers who had been lecturers or associate professors at leading Japanese medical schools and were temporarily employed by the Japanese Army. Why did they join these "factories" and become murderers? Was it impossible to stop the massacre, or at least to avoid participation? I have found three explanations for the lack of opposition by medical professionals.

First, in Japan there was then prevailing pressure for their participation. As it was in wartime and they lived in a fascistic country, it was very common to cooperate with the military. They would be blamed as "Hikokumin" (traitors) if they refuse to participate. They accepted their fate without trying to resist it, even when they knew what they would be assigned to do in China [cf. Yoshikai (1981), p.65ff.].

Second, they were ordered by their academic superiors to go to China. In Japanese medial schools, even now, head professors exercise supreme power over their staff. Usually, there is only one professor in each "Ikyoku" (department), which is at the same time an office of clinical practice, a faculty for graduate education, and a research laboratory. I believe this Ikyoku system is very unique to the Japanese medical profession. Even after earning a doctoral degree, researchers devote themselves to the Ikyoku, hoping to be nominated by the head professor as his successor. They cannot oppose their professors because rejection of the professor's order, for example to go to a certain facility, would result in excommunication from the Ikyoku, in effect forcing them to abandon their academic careers.

In that wartime, being in short supply of research facilities at Universities, professors were willing to be cooperative with the army and Lt. Surgeon General Ishii. The professors promised Ishii to send their best disciples to his factories, and, in return, Ishii and the army supplied enough research equipment (and sometimes even the data and chances of human experimentation) to the professors [cf. Tsuneishi (1994), Chapter 3]. This tells us that the massacre by human experimentation in China would have been impossible without the support of the leading medical professors in those days and that not only Ishii and the army but also the Japanese medical profession itself is guilty of the crime. That is why the term "Jintai Jikken" (experimentation with human beings) has become a taboo utterance in the Japanese medical establishment since then.

Third, even for the reluctant researchers from the Universities, Ishii's factories were luxurious places. For example, the annual budget of Unit731 was 10 million yen (about 9 billion yen in the modern currency, or about86 million dollars, at present value). Half of this budget was for research, and the other half was for labor costs for about 3,000 employees (2). The salary was considerably high, and the food served there was wonderful. Also, Unit 731 had the most luxurious laboratories of Japan then. Surely there was a massacre: there was a hell. But for those who could concentrate on research, it was a nice place. There was nearly no restriction on their research--they could even treat human subjects truly as guinea pigs. In addition, there were patients with diseases that they could hardly ever observe in the Japanese homeland, for example, epidemic hemorrhagic fever, plague, typhus, and severe frostbite. They could produce brilliant scientific achievements for Japanese medicine, although these achievements obviously could not be published internationally. With these achievements, they could gain good positions in the Japanese medical establishment after the war.

Concluding Remarks

I have no intention of justifying the conduct of the Japanese Army and Japanese doctors in China during World War II. What I would like to do is to understand why they did and could do such things, to learn how we can forever prevent such an outrageous enterprise.

Among the circumstances described above, I found the absolute power of the professors over their disciples to be very characteristic of the Japanese system, in contrast with the Nazi human experiments and the U.S. human radiation experiments. This absolute authority was possible on the basis of the authoritarian character of Japanese (and probably East-Asian) ethics. I find some virtues of Japanese and East-Asian ethics, such as respect for authority and harmony, in the behavior of those doctors. In fact, the "Ikyoku" system in the Japanese medical profession is supported by these virtues.

I believe it is the Japanese and East-Asian values, such as respect for authority and harmony, in the Japanese medical profession that not only made possible the massacre by human experimentation in China during the period of 1933-1945 but also prevented a public investigation after the war. That is why I entirely disagree with Japanese proponents of "the East-Asian Bioethics" who have never mentioned the past conduct of the Japanese medical profession. For Japanese bioethicists, it is dangerous, shameful, and outrageous to discuss a "moral community" among East-Asian countries without serious reflection on the past acts of Japan.


(1) For more detailed description, see Harris (1994). This is so far the most comprehensive English-written book on this issue, although it does not mention experiments and vivisections performed at the Manchuria Medical School and army hospitals. On these experiments and vivisections, see Honda (1972), Chinese Central Archive et al. (1991), and Yoshikai (1981).

(2) According to the testimony of Major General Kiyoshi Kawashima at the Kaharovsk Trial, December 25, 1949, in Materials on the Trial of Former Servicemen of the Japanese Army Charged with Manufacturing and Employing Bacteriological Weapons (1950).


Chinese Central Archive et al. (eds.). (1991) Seitai Kaibo: Kyu Nihongun no Senso Hanzai (Vivisection: Japanese Army's War Crime), Japanese translation, Dobunkan.

Harris, Sheldon H. (1994) Factories of Death: Japanese Biological Warfare,1932-45, and the American Cover-Up, Routledge.

Honda, Katsuichi (1972) Chugoku e no Tabi (A Journey to China), Asahi Shimbun Sha (reprinted in Asahi Bunko, 1981).

Materials on the Trial of Former Servicemen of the Japanese Army Charged with Manufacturing and Employing Bacteriological Weapons (1950), Moscow: Foreign Languages Publishing House.

Tsuneishi, Kei'ichi (1994) Igakusha Tachi no Soshiki Hanzai (The Conspiracy of Medical Researchers), Asahi Shimbun Sha (reprinted in Asahi Bunko, 1999).

Yoshikai, Natsuko (1981) Kesenai Kioku: Yuasa Gun'i Seitaikaibo no Kiroku(Unforgettable Memory: A Document of Army Surgion Yuasa's Vivisection), Nitchu Shuppan.

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