The Political Dimensions of Bacteriological Warfare and the Experiments of Japan’s Unit 731 (1931–1948)

Abstract

Between 1931 and 1937, Japanese military doctrine shifted toward the development of an independent biological warfare program by exploiting the loopholes of the 1925 Geneva Protocol. The Japanese occupation of Manchuria in 1931 and the establishment of the puppet state of Manchukuo in 1932 created an isolated environment that enabled military physician Shirō Ishii to transfer his research from the laboratory to coercive human experimentation through the Tōgō Unit at Beiyinhe between 1932 and 1933. Following Japan's withdrawal from the League of Nations in 1933, the project gained official status with the issuance of the 1936 decrees establishing the Epidemic Prevention and Water Supply Department of the Kwantung Army, which later became the organizational foundation of Unit 731. The program expanded with the outbreak of the Second Sino–Japanese War in 1937. Between 1938 and 1940, the Pingfang site was transformed into a fortified military medical complex comprising eight divisions and the and a field testing ground, in coordination with official Japanese universities and through the implementation of a special referral system to supply the laboratories with Maruta prisoners. The unit then moved from laboratory and field experiments to launching aerial biological attacks against the cities of Quzhou, Ningbo, and Changde between 1940 and 1942, resulting in numerous deaths. On the eve of the Soviet intervention and Japan's surrender in August 1945, the Kwantung Army leadership hastily bombed the Pingfang facilities and liquidated the prisoners to hide the crime. However, the course of justice ended with a secret intelligence deal struck with the American command between 1946 and 1947, by order of General MacArthur, granting Ishii and his commanders immunity from prosecution in the Tokyo court in exchange for handing over data on human experiments. By 1948, this effectively entrenched the judicial marginalization and political cover-up of the Japanese Bacteriological warfare file.