The former site of the Imperial Japanese Army’s Medical College where many human bones were unearthed in July 1989 in Tokyo’s Shinjuku Ward (Asahi Shimbun file photo)

On the 30th anniversary of the discovery of mysterious human bones in Tokyo, a citizens group is renewing its efforts to connect them to the human experimentation conducted by the notorious Unit 731.

“We hope to create a movement that leads to the confirmation of the identity of these remains,” said Kazuyuki Kawamura, 67, who heads the Association Demanding Investigation of Human Bones Discovered from the Site of the Army Medical College.

His group will hold an exhibition and site tours in Tokyo from July 19 to shed light on the wartime atrocities committed by the covert chemical and biological weapon research unit.

On July 22, 1989, hundreds of bones were dug up at a construction site for the then Health and Welfare Ministry’s research facility in the Toyama district of Shinjuku Ward.

Until the end of World War II, the Imperial Japanese Army operated a medical school at the location.

The army’s epidemic prevention research laboratory that had deep connections to Unit 731 was part of the medical school.

The unit, which studied germ warfare, is believed to have carried out experiments on Chinese people to develop biological and chemical weapons during the war.

Immediately after the excavation, locals and researchers raised the possibility that these bones belonged to victims of some of those experiments.

The ministry, however, treated those remains as John and Jane Does and asked the ward office to bury them.

Upon a request from the ward office, experts investigated and analyzed the skeletons. They concluded that the bones belonged to more than 100 people of Mongoloid origin, which is an Asian race.

The bones had been buried for at least a few decades and as long as 100 years, experts said in their conclusion announced in 1992.

Most of the remains are of male adults, and some bear traces of being stabbed and cut before death. Some bones also show marks of being struck by bullets posthumously, experts said.

The ministry then questioned related officials of the Imperial Japanese Army’s Medical College about the bones.

In 2001, the ministry announced the results of the investigation, saying the excavated remains were part of the corpses collected for research purposes at the medical school, and included those who were killed in action.

But their identities and how and where these bones came from remain a mystery, the ministry concluded.

The bones have since been placed in a charnel set up near the excavation site.

Kawamura was a Shinjuku Ward assembly member when the bones were excavated. He has since come to believe that some of the remains belong to victims subjected to the human experiments conducted by Unit 731.

Kawamura and researchers and school teachers who share the belief established the group and urged the ward office and the central government to preserve the remains and conduct a full investigation.

Exactly 30 years have passed since the excavation. Hoping to seize on the anniversary, the group will host a series of events between July 19 and July 21 at Toyama Sunrise, a facility near the discovery site.

Kawamura will give a talk on July 21.

Walking tours will be offered on July 20 and July 21 of several former Imperial Japanese Army sites in Shinjuku Ward, with a fee from 500 yen ($4.60) to 1,000 yen.

For more information on the event: http://jinkotsu731.web.fc2.com