Workers in Tokyo dug up the bones of at least 62 people at the old Army Medical School in 1989, and Japan has never identified them

On 22 July 1989 workers building a Health Ministry research institute on the site of the wartime Army Medical School in Tokyo dug up about a dozen skulls, many with cuts, and other bones. Some skulls had holes drilled in them or sections cut out. Police found no evidence of a crime. A 1992 anthropological study found the bones came from at least 62 people, possibly more than 100, mostly adults from parts of Asia outside Japan. The cuts were made after death. In 2001 the Health Ministry, after questioning 290 people, said the bones were probably from bodies used in medical education or brought from war zones, and could not be linked to Unit 731, the army unit reported to have carried out human experiments in northeast China. In 2006 Toyo Ishii, a former nurse aged 88, said staff had been ordered to bury corpses and body parts at the site before American troops arrived. On 21 February 2011 the government began a 100 million yen excavation. In July 2024 activists marked 35 years since the discovery. Kazuyuki Kawamura obtained 400 pages of the ministry's 2001 material and said key information was excluded. The ministry said no label or record links the bones to anyone, which makes DNA testing difficult. The bones remain in a Tokyo repository.