The existence of Unit 731 was a well-guarded secret, by Japanese and American officials alike, and would have remained forever unknown to the wider world if a student from Keio University in Tokyo hadn’t in 1984 come across a box of incriminating documents in a second-hand bookshop and brought them to the attention of others.27 By this time it was far too late to bring to justice Shiro Ishii. He had died in 1959, peacefully in his sleep, at the age of sixty-seven after nearly a decade and a half of untroubled post-war life.
