Men Behind the Sun

Men Behind the Sun (, literally Black Sun: 731, also sometimes called Man Behind the Sun) is a 1988 Hong Kong historical exploitation horror film directed by T. F. Mou, and written by Mei Liu, Wen Yuan Mou and Dun Jing Teng. The film is a graphic depiction of the war atrocities committed by the Imperial Japanese Army at Unit 731, the secret biological weapons experimentation unit of the Imperial Japanese Army during the Second Sino-Japanese War. It details the various cruel medical experiments Unit 731 conducted on Chinese and ethnic Russian prisoners towards the end of the war.

It is the first film to be classified "level III" (equivalent to the US rating NC-17) in Hong Kong.

Plot
The film opens with the passage "Friendship is friendship; history is history."

A group of Japanese boys are conscripted into the Youth Corps. They are assigned to the Kwantung Army, and are brought to one of the facilities serving Unit 731, which is headed by Shiro Ishii. Soon, they are introduced to the experiments going on at the facility, for which they feel revulsion. The purpose of the experiments is to find a highly contagious strain of bubonic plague, to be used as a last-ditch weapon against the Chinese population.

Meanwhile, the young soldiers befriend a local mute Chinese boy with whom they play games of catch. One day, the commanding officers ask the boys to bring the Chinese child to the facility. Naively, they follow orders believing that no real harm will come to the boy; however, the senior medical staff vivisects the boy and keeps his organs for research. When the young soldiers realize what has happened, they stage a minor uprising by ganging up and physically beating their commanding officer.

After a revelation, Dr. Ishii develops a prototype ceramic bomb that does not kill the infectious fleas inside upon being launched. To test its efficacy, he orders several Chinese prisoners to be tied to crosses. However, the experiment is botched since the Japanese aerial forces are retreating. Chinese prisoners break free from the crosses, and attempt to escape; however, Japanese troops hunt them down, and nearly all of them are run over or shot, including several Japanese.

Unit 731 overhears the atomic bombings of Hiroshima and Nagasaki and Russia's declaration of war. Dr. Ishii initially orders his subordinates and their families to commit suicide, but is persuaded instead to evacuate them and only commit suicide if captured. Afterwards, Unit 731 destroys evidence of their research, including gassing the surviving test subjects to death and blowing up the facilities.

That night, the Japanese troops and their families wait at the train station to arrive home to Japan. One lone survivor of Unit 731, having disguised himself as a Japanese soldier, attacks one of them but is impaled by a Japanese flag. The Youth Corps clutch onto the blood-stained flag in horror as they depart the station.

The closing passages reveal that Dr. Ishii cooperates with the Americans, giving them his research and agreeing to work for them. Years later, he is moved to the Korean War, and biological weapons appear on the battlefield shortly thereafter. The Youth Corps involved with 731 are revealed to have led hard lives after the war, with their educational background being stigmatized.

Controversy
Though Mou claims he was trying to depict historical accuracy with the film, he has been criticized by Hong Kong critics that the film's appearance as an exploitation film negates any educational value involving a historical atrocity, and Japanese critics deemed the film as anti-Japanese propaganda. American horror critics have deemed the film as genuinely horrifying, but lacking in writing or narrative structure while agreeing with Hong Kong critics regarding its lack of educational value, and as such the film has had no official US release.

Because of its graphic content, the film has suffered mass controversy with censors all over the world. It was originally banned in Australia and caused public outcry in Japan to such an extent that director Mou even received threats on his life. The film was given several minutes of mandated cuts to be allowed a release in the United Kingdom.

The film garnered further controversy for its use of what Mou claims to be actual autopsy footage of a young boy and also for a scene in which a live cat appears to be thrown into a room to be eaten alive by hundreds of frenzied rats. In the 2010 documentary Black Sunshine: Conversations With T.F. Mou, Mou confessed that the cat was tired after participation in the film and got two fish as a reward, that the cat was made wet with honey and theater blood (as opposed to real blood like other scenes as the rat would attack otherwise), and that the rats were licking and eating the honey only.

Reception
From contemporary reviews, "Lor." of Variety declared the film to be a "lowbrow exploitationer treating a serious subject, Japanese war atrocities." noting that "Explosive material is dramatically potent and could have been handled tastefully, as with Kon Ichikawa's classic films like Fires on the Plain" but "resorts to nauseating sensationalism, with butcher-shop depiction of autopsies on live subjects, a disgusting "decompression" experiment spewing intestines out of a victim and a horrendously realistic scene of a pussycat bloodily mauled by a room full of rats."

Sequels
The film spawned three standalone sequels:
 * Unit 731: Laboratory of the Devil (黑太陽731續集之殺人工廠, 1992)
 * Unit 731: A Narrow Escape (黑太陽731完結篇, 1994)
 * Black Sun: The Nanking Massacre (黑太陽─南京大屠殺, 1995)