As for beliefs, aren't there some sort of beliefs involved in all wars? Weren't the Japanese under the impression that they were superior to everyone else and thus entitled to treat prisoners like non-humans. Is there a difference if a japanese soldier in uniform cut off some ones head or an arab in tribal robes? The Japanese believed that the rest of the world was not as good as them, Muslims believe that the rest of the world is not as Godly as they are. What is the difference?