IIDA, Nagano Prefecture—Hideo Shimizu has been frustrated by the reluctance of a peace memorial museum here to display panels about the infamous Unit 731, where he worked during World War II.

The former Imperial Japanese Army unit carried out human experiments on prisoners to develop biological weapons in Harbin in former Manchuria, and it was also engaged in germ warfare, according to a Tokyo District Court ruling in 2002.

The museum was expected to show eight panels on Unit 731, including some featuring testimonies by Shimizu and other former members, when it opened in May last year as a municipal facility where people learn about war and peace.

But the municipal board of education, which operates the museum, said it needs to carefully consider the issue because academic research is still being conducted on Unit 731 and diverse opinions exist in society.

The board also said it has taken into account requests from citizens groups and teachers to avoid “extreme contents.”

In one testimony featured on a panel, a former Unit 731 member said as many as 300 people were vivisected. Another said experiments were conducted on prisoners after chloroform was injected.

The testimonies were to be accompanied with the names and photos of the former members.

Shimizu, 93, who belonged to a unit of minors in Unit 731, said he discovered containers holding human bodies preserved in formalin in a specimen room on the second floor of the headquarters building in July 1945.

He said the lower part of a pregnant woman’s body was laid open to display the fetus.

“Unless what we did is handed down to future generations, we can never ‘pray for peace,’” said Shimizu, referring to part of the museum’s official Japanese name.

Shimizu, who has spoken about his wartime experiences in public, said he has been attacked as a liar.

Unit 731’s germ weapons development activities were recognized as facts by the Tokyo District Court based on testimonies by former members and researchers in a compensation lawsuit filed by Chinese bereaved family members against the Japanese government.

The government, meanwhile, told the Diet in 2003 that it had not confirmed any documents showing Unit 731 was engaged in germ warfare among those kept at the Foreign Ministry and the Defense Agency, the present-day Defense Ministry.

The Imperial Japanese Army demolished Unit 731 facilities and destroyed related documents immediately before the war ended. It is said that former members were ordered not to disclose the unit’s activities.

In response to criticism from Shimizu and others, the Iida board of education started discussing the contents of the Unit 731 display at a committee in February.

At a meeting in March, the committee decided to exhibit a panel display by referencing the unit’s activities as recognized by the Tokyo District Court ruling.

Still, discussions are ongoing about what to do with the testimonies of the former members.

The Iida board of education’s initial decision may not be an exception.

Masahiko Yamabe, 77, a former curator at the Center of the Tokyo Raids and War Damage, said a growing number of public facilities, such as history and peace museums, are not featuring exhibits on Japan’s history as aggressor when they open or are dropping such exhibits during renovations.

“It appears that local governments are imposing self-restrictions, fearing protests from the outside,” he said.

A citizens organization has been annually holding an exhibition on Japan’s wartime aggression, featuring photos about Unit 731 and the Nanking Massacre of 1937, at Kanagawa Kenmin Center, a prefectural government facility in Yokohama, since 2016.

Every time, organizers received complaints.

“It will do Japan no good if you exaggerate only the facts of aggression,” said Tadakuni Takahashi, 79, who heads a group that lodged a protest. “I do not want my children and grandchildren to live being ashamed of themselves.”

Kenji Takeoka, a former elementary school teacher who planned the exhibition, disagrees.

“We cannot share a common understanding with people victimized by Japan’s aggression unless we squarely face up to the history of aggression,” said Takeoka, 76. “Without our exhibition, the history of aggression will be forgotten as the number of people who experienced the war is declining.”

Takeoka’s organization plans to hold the exhibition this summer, too.