Men Behind the Sun (Chinese: 731 / 731; pinyin: hi ti yng 731,literally meaning "Black Sun: 731") is a 1988 Hong Kong film directed by Mou Tun Fei.
The film is a graphic depiction of the war atrocities committed by the Japanese at Unit 731, the secret biological weapons experimentation unit of the Imperial Japanese Army during World War II. The film details the various cruel medical experiments Unit 731 inflicted upon the Chinese and Soviet prisoners at the tail-end of the war.
This is the first movie to be rated "III" (equivalent to the US rating NC-17) in Hong Kong.
