Quick Facts on Unit 731

by Isabel Shiao

Unit 731 of the Japanese Imperial Army was established in the context of rapid modernization, the aftermath of WWI, and the global rise of fascism. The Meiji Restoration transformed Japan into a highly industrialized nation, eager to become as powerful as Western states. This process raised concerns about the lack of resources and habitable land, prompting Japan to expand throughout Asia and form colonies. Thus, in 1931, Japanese forces invaded Manchuria and created the puppet state of Manchukuo to obtain the land’s valuable resources and extra living space to solve Japan’s overpopulation problem. However, as Sheldon Harris notes in his book, Factories of Death, Manchuria was turned into “one gigantic biological and chemical warfare laboratory” (Harris 5) to fulfill the nation’s quest for hegemony. ​

It is important to note that it was not politicians or military agencies that led the movement towards biological warfare; in both Germany and Japan, the nations’ respective leading scientists initiated the research. Ishii Shiro was a graduate student at Kyoto University, studying bacteriological, serological, and pathological sciences. He traveled to 25 European and American countries and ultimately “observed that research on biological warfare had not advanced in Japan” (Wang Xuan 11). After being appointed to the Minister of Epidemic Prevention in the Kwantung Army, he enthusiastically promoted the development of biological warfare weapons. Like other prominent scientists, Ishii observed its potential in defeating entire armies in WWI. The Geneva Protocol of 1925 that called for the prohibition of such weapons was not ratified in Japan, and Japan’s withdrawal from the League of Nations in 1933 allowed Ishii’s network of over 10,000 scientists to secretly develop their research as early as 1931 without international restraint.
Hundreds, if not thousands, of Chinese prisoners and other allied POW’s were subjected to human experimentation in underground research facilities. Marutas, the Japanese term for “logs,” were subjected to intense pressure chambers, exposure to deadly diseases like the bubonic plague and anthrax, and live vivisection without anesthesia. It has been theorized that the term “marutas” was used to dehumanize the subjects, thereby allowing the scientists to conduct their research without hesitation. Unit 731 tested its weapons by releasing plague bombs and contaminating water sources in the Chinese countryside. Much of the local population was killed, and those who survived were left with rotten legs that often condemned the victims to a life of poverty. Between the years of 1939 and 1945, it is estimated that these experiments “killed and poisoned more than a million Chinese, Koreans, Mongolians, and Russians … The Chinese countryside alone suffered more than 250,000 deaths as a consequence of Japanese biological warfare” (Wang Xuan 4).
Despite the severity of these war crimes, most of the members in Ishii’s network were not prosecuted or even tried at the end of the war. The United States government granted scientists immunity in exchange for the scientific data collected during the experiments. This information would later be used to create deadly biological weapons in the Korean War. 

Sources
Harris, Sheldon, Factories of Death: Japanese Biological Warfare, 1932-45 and the American Cover-Up (Routledge, 2002).
Chan, Jenny & Dybbro, Danielle, “Seeking Justice for Biological Warfare Victims of Unit 731: Evidence Collected by Wang Xuan”.

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