Hideo Shimizu, 96, is one of the few surviving former members of Unit 731 to publicly expose the crimes committed by the Japanese germ-warfare unit during World War II. In August 2024, Shimizu returned to Harbin, Northeast China's Heilongjiang Province, where he offered a sincere apology to Chinese victims and their families. To document the crimes of the Japanese army, People's Daily reporters spent more than two years conducting over a dozen interviews with Shimizu and cross-checking his accounts against evidence from multiple sources. His firsthand testimony offers a rare and invaluable historical record of Japanese aggression.