Men Behind the Sun tells the horrific story of Japanese prisoner camp 731 which doubled as a chemical warfare lab during World War II. Within this camp, the use of live humans in experimental weapons testing is witnessed by a group of teenage Japanese who have been sent there for training. Their experiences within the camp basically provide the framework for the director with which he can show repulsive acts of torture and brutality. When the young soldiers are first brought to the camp, they are forced to look at the Chinese and Russian prisoners as "maruta," which means kindling, or firewood. Basically, an inanimate object that provides use to others. In a separate plot line, the camp is being returned to the control of Lieutenant General Shiro Ishii, the head of chemical weapons experimentation in Japan. He can sense that the war is turning against Japan and is desperate to come up with the ultimate weapon that will turn the tide in his emperor's favor.

I went into Men Behind the Sun with a lot of pre-existing notions on how disgusting it was going to be. I had read reviews that said that it was one of the most vile films people had ever seen and ranked up there with “Cannibal Holocaust” as the most disturbing movie of all time. Needless to say I was not looking forward to the experience, but I wanted to form my own opinion. Before I get to the experiment scenes, I'll say that the acting and directing is really quite good. The teenage soldiers are likable and you can see the conflict they are going through with what they are witnessing. They have undying allegiance to their emperor, but the acts performed on the prisoners are those that no one should have to bear. The adults in the film however, save for one or two, are completely committed to their jobs and carry out their experiments with not a single moment of moral clarity. The experiments they perform on people range from the quick and relatively painless to drawn out horrors that are difficult to watch. One woman has her arms tied down to a block of wood while soldiers pour ice water over her bare arms. It being winter, her arms eventually develop severe frost bite and are virtually useless. They lead her inside where she is told to place her arms in near-boiling water. When she removes them the doctors grabs her forearms and literally rips the flesh from her bones and leaves it hanging in strips from her fingers. Another prisoner is forced to have his hands flash frozen after which his fingers are shattered into fragments with a hammer. There is also an actual autopsy performed on a child's body that is extremely tough to watch. However, the worst scene involves a naked prisoner thrown into a pressure chamber. I won't describe what happens, but suffice to say it was by far the most disturbing thing I've ever seen in a movie. There is also a scenes where a live cat is thrown into a pit of rats. I read many people's thoughts on this scene and the contention that this was real, but I have to disagree. Although it is well edited, there are many factors that lead me to believe that the scene is faked. What is seemingly not faked is later when the rats are doused with gasoline and set on fire, causing them to scurry in every direction screeching in pain.

The director stated in an interview (a written version is included on the DVD) that he wanted to make people aware of the horrors that the Japanese army committed during the war, especially on the Chinese. If that was his plan, he certainly succeeded. This is not a film that you are likely to forget anytime soon, not only because of the horrendous scenes you witness but also because of the realization that this and other horrible acts really occurred during the Japanese occupation of northeastern China.