[[caption-width-right:350:The director T.F. Mou [[{{Anvilicious}} subtly presents]] the message of the film.]]

One of the most disturbing films to ever come out of Eastern Asia.

Released in 1988, ''Men Behind the Sun'' (''Hei tai yang 731'', ''The Black Sun Unit 731'' in native Hong Kong) is a film about the Imperial Japanese Army's Unit 731, which during World War II conducted medical research and biological/chemical weapon experiments on captive human subjects. The film details many of the experiments carried out by the unit, and also follows a group of recruits to the unit's Youth Corps.

''Men Behind the Sun'' is supposed to be a rather horrifyingly accurate depiction of Unit 731's activities in real life. However, the director based it on a fictional novel serialized in a Japanese Communist Party newspaper of questionable quality, to which can be traced the origins of many dubious facts regarding the Unit. Whether the film is a cheap ExploitationFilm or a valid commentary on the behavior of the Japanese Army is debated. Either way, it's almost guaranteed to ruin your day.

!!This film provides examples of:

* AdultFear: The gas chamber experiment.
* BasedOnATrueStory: Most or all of the experiments depicted actually took place, as did most of the historical background.
* BodyHorror
* CouldntFindAPen: One of the ''maruta'' scrawls a condemnation of his captors on the wall of his cell in his own blood [[spoiler:when they're all gassed to death.]]
* CruelAndUnusualDeath: The guy in the pressure chamber.
* CyanidePill
* EvilIsHammy: Shiro Ishii, especially when he demonstrates his new bacterial bomb.
* ExploitationFilm: Unintentional, but is regarded as such my some.
* ForScience: War or not, this was the justification for many researchers.
* GasMaskMooks
* {{Gorn}}: Including a real cadaver, cut open on film.
* HarmlessFreezing: Averted.
* HazmatSuit
* KarmaHoudini: As the film points out, Ishii and most of his men escaped judgment after the war.
* KickTheDog: Except it's not a dog, it's a cat. And it's not kicked, it's [[spoiler:eaten alive by rats.]] Also, the mute child is either kicked or [[ShootTheDog shot]], depending on one's view of the scientific value of the act.
* KillItWithFire: Unit 731's rat colony is disposed of with fire at the end.
* LeaveNoSurvivors: When [[spoiler:Japan surrenders and Unit 731 is ordered to disband.]]
* MadDoctor
* MadScientist
* MedicalHorror
* MorallyAmbiguousDoctorate: And how.
* NoAnimalsWereHarmed: {{Played straight}} with the infamous scene of the cat being devoured by rats; it was red-dyed honey and the cat was rewarded with fish before being sent home to its owner. Averted with the rats themselves, [[spoiler:which were actually set on fire.]] No word either way on the gas chamber dove.
* PleaseIWillDoAnything: {{Invoked}} word-for-word.
* RuleOfSymbolism: The image at the top comes from a scene at the end in which someone attacks Ishii and the other 731 leaders for their crimes. The attacker is stabbed with a flag pole. This unlikely weapon is used primarily so that we can see the Japanese flag soiled with blood.
* SequelDecay: The film was followed by several sequels, none of which were anywhere near as shocking as the original.
* SlowClap: When Ishii demonstrates his low-temperature bacterial bomb.
* StrappedToAnOperatingTable
* TheSpeechless: A mute child serves as an excellent dog for kicking.
* WouldHurtAChild: Several.