The education board of Iida city in Nagano Prefecture, central Japan, is at loggerheads with local citizens involved in a peace museum exhibit, as they grapple with calls for greater focus on "biological warfare" testing by the Imperial Japanese Army's notorious Unit 731 on prisoners of war.

Known officially as the Epidemic Prevention and Water Purification Department of the Kwangtung Army, Unit 731 is thought to have undertaken covert biological and chemical warfare research in China, engaging in lethal experimentation and testing on humans during World War II.

The special unit, also known as Manshu Detachment 731, was based in the suburbs of Harbin in the puppet state of Manchuria, now northeastern China, from 1936 to 1945. Prisoners of war were secretly experimented upon to develop, among other things, plague and cholera-based biological weapons, according to historians.

While the local citizens have pushed for displaying clearer details at the exhibit about the atrocities committed by Unit 731 and have called for the testimonies of its former members from the prefecture to be featured, the Iida City Board of Education, tasked with managing the museum, remains cautious.

Photo taken in October 2022 shows medical equipment that was used by the Imperial Japanese Army's notorious Unit 731 on display at a peace museum exhibition in Iida, Nagano Prefecture. (Kyodo)

To break the impasse, the board proposed a plan in March to introduce court rulings acknowledging the unit's engagement in "human experiments on prisoners of war and the development of biological weapons."

While some of the local residents involved in the project have shown their understanding, others have maintained reservations, arguing that it is difficult to interpret the content of the rulings or what the displays intend to convey about Unit 731 in a way that is understandable to the public.

The museum opened in May 2022 for people to "learn about the tragedy of war and the importance of peace, and to talk about the reality of war with generations to come," by displaying various items from the conflict, gathered in a collaborative effort between the citizens and the board.

Members of the public prepared testimonies about Unit 731's human experiments, as well as its biological war programs, by some of its former members from Nagano Prefecture to be exhibited in panel displays.

But just before the museum was officially opened, the city's board deferred a decision to display the testimonies, citing a 2003 central government statement to the Diet that said, "no documents have been confirmed to show that biological warfare was carried out."

As a result, the museum exhibit contains nothing that seeks to explain the unit's activities, instead showing only medical tools they used and other items purported to have been brought home by former members of the unit.

In February, after the developments caught the attention of the media, the board formed an educators' committee, which also included some citizens within the prefecture, hoping to exchange opinions about how the exhibition should be presented.

At a March committee meeting, the board presented a draft proposal for a display at the exhibition on Unit 731. The proposed display included excerpts from the Supreme Court's 1997 ruling about the unconstitutionality and illegality of the education minister's screening of school textbooks referencing the unit.

Photo taken in March 2023 shows a committee established by the Iida City Board of Education in Nagano Prefecture exchanging opinions on how a peace exhibit concerning the Imperial Japanese Army's notorious Unit 731 should be displayed. (Kyodo)

It also included excerpts from the Tokyo District Court's 2002 ruling on a damages suit, filed against the Japanese government by Chinese victims of Unit 731 and their families. Both verdicts acknowledged that the unit had indeed engaged in biological warfare, and the move was considered a compromise.

But some citizens on the committee said that the verdicts are difficult to understand due to the "excessive adherence to accuracy" about Unit 731's activities, and stressed the need for careful explanations that could be easily understood by children visiting the museum.

Another local resident involved in the project said, "The whole concept of the exhibition should be worked out anew to clarify what can be properly communicated."

The education board, which says that the display of testimonies by members of Unit 731 is a separate issue from the verdicts proposed for the exhibit, is set to continue exchanging opinions through the committee.

During the conflict, Unit 731 was joined by medical personnel from universities around Japan. In recent years, the National Archives of Japan has disclosed a list of the unit's members, as well as documents related to its withdrawal from Harbin, though research is still ongoing.