Sworn to secrecy by the Japanese Imperial Army, Hideo Shimizu carried the horrors he saw at the notorious Unit 731 facility with him for more than 70 years. The 93-year-old was just 14 when he was drafted as a cadet to the city of Harbin, in what was then Japanese-occupied Manchuria, during World WaR 2. There, he was groomed to take part in some of history's worst atrocities - human experiments carried out on prisoners of war including pregnant women and small children. More than 3,000 people - mostly Chinese civilians, but also Russian, British and American POWs - were...