Photo/Illutration The staff list of Unit 731, discovered at the National Archives of Japan, displays the names of top officials. (Provided by Seiya Matsuno, a researcher of Japanese modern and contemporary history at Meiji Gakuin University’s International Peace Research Institute)

An exceptionally rare document listing the names and ranks of members of the Imperial Japanese Army’s notorious wartime Unit 731 has turned up in Tokyo.

It is the first time for such a record to surface that details both the organization’s personnel and organizational structure.

The document was discovered among materials kept at the National Archives of Japan by Seiya Matsuno, a researcher of Japanese modern and contemporary history at Meiji Gakuin University’s International Peace Research Institute.

Officially known as the Epidemic Prevention and Water Purification Department of the Kwantung Army, Unit 731 operated in a suburb of the northeastern Chinese city of Harbin.

Unit 731 was responsible for some of the most notorious war crimes committed by the Japanese army. It conducted biological experiments on Chinese and Russian prisoners and developed bacterial weapons. 

The covert unit’s facilities in what was then called Manchuria were destroyed immediately before Japan’s defeat in World War II in 1945. Relevant documents were ordered to be destroyed.

Only very limited records on the corps are known to exist, rendering it difficult to expose the true scope of the horrors perpetrated by Unit 731.

The document was found in a report on the reorganization of the Kwantung Army in August 1940.

It states that Unit 731’s name was changed from the Epidemic Prevention Department to the Epidemic Prevention and Water Purification Department. Additional personnel were deployed to the unit as it expanded its scale of operations.

Appended to the report was the staff list of Unit 731.

Surgeon Col. Shiro Ishii, the first director of Unit 731, is described as its top official. The names, affiliations and ranks of 97 senior officers are referred to as well.

“A characteristic is that many medical experts sent from universities are counted among the executives as ‘technicians,’” said Matsuno. “What the unit was like around the time of its introduction has become clear for the first time.”

A similar personnel list dating from 1945 emerged some years ago at the National Archives.

The document was made publicly available in 2016, when Katsuo Nishiyama, professor emeritus of social medicine at Shiga University of Medical Science, petitioned for its disclosure.

It details the names and addresses of those who belonged to the unit shortly before the war ended.

But other details, such as its organizational composition, could only be deducted based on accounts of individuals and recollections during court trials and elsewhere.

“The latest discovery is important because until now each member’s affiliation and personnel replacement could not properly be determined,” said Nishiyama. “Now, we have been able to retrace what happened to some members by comparing the older staff list with the one that has just surfaced.”

Matsuno said his discovery could shed light on the postwar movements of top Unit 731 officials.

“Some formerly unknown technicians appear on the list,” Matsuno said. “The document may help figure out how they regained their standing in medical circles and the pharmaceutical industry after the war.”

Nishiyama noted that many medical experts earned degrees following the end of World War II based on their studies at Unit 731.

“We must look at why the medical world and university operators involved in the unit’s activities did not reflect on their misconduct even after the war ended,” he said.

The staff list of Unit 100, or the Kwantung Army Warhorse Disease Prevention Shop for biological warfare research, was also among the cache of recently discovered documents. Veterinary servicemen worked for the unit.

(This article was written by Ryota Goto and Senior Staff Writer Ryuichi Kitano.)

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