Zstar asks "Was it policy (for the Imperial Japanese Army) to eat humans?"
To the best of my knowledge, it was forbidden for Japanese Imperial Army troops to eat their own dead, but the eating of enemy prisoners of war and enemy dead was not specifically covered by orders.
The issue of Japanese cannibalism appears to have arisen most commonly in New Guinea and other Pacific Islands. In some cases starvation was put forward as an excuse for this behaviour. In other cases, it appears to have taken place as a form of ritual in the officers' mess and appears to have involved the eating of bodies of executed Allied airmen. As you are probably aware, the Japanese went to extraordinary lengths at the end of the war to destroy documentary evidence of their numerous war crimes, and most of the cases mentioned below came to light from eyewitnesses who survived imprisonment.
Three very highly regarded books are worth consulting on this unpleasant aspect of Pacific War history:
"The Knights of Bushido" (1958) by Lord Russell of Liverpool. This is the classic work on Japanese war crimes. Lord Russell was a former senior war crimes prosecutor, and also wrote "The Scourge of the Swastika". Lord Russell mentions one extraordinary case of ritual cannibalism of a captured American airman and quotes verbatim the Japanese document containing detailed instructions concerning the manner in which this war crime was to take place. A Japanese general and a senior Japanese naval officer were present in the mess when this cannibalism occurred.
"Horror in the East" (2001) was written by Laurence Rees who also produced the acclaimed BBC documentary of the same title.
"Prisoners of the Japanese" (1994) by Gavan Daws; reprinted 2004 by Scribe Publications.
None of these works makes any attempt to sensationalise the issue of Japanese cannibalism, and perhaps that serves to make the documented cases even more horrifying.
If you want convenient access to several documented examples of Japanese cannibalism you might like to click on the Japanese war crimes section of my Pacific War Web-site at:
http://www.users.bigpond.com/battlefora ... Intro.html
The cases that I have mentioned are all sourced to the books mentioned above.