Men Behind the Sun

Men Behind the Sun (Chinese: 黑太陽731; lit. 'Black Sun: 731') is a 1988 Hong Kong historical horror film directed by Mou Tun-fei. It is a graphic depiction of the war atrocities committed by the Empire of Japan at Unit 731, the secret biological weapons experimentation unit of the Imperial Japanese Army during the Second Sino-Japanese War. It was the first film to be classified "level III" (equivalent to the US rating NC-17) in Hong Kong.