At the end of the Word War II, the occupying American forces made the practical decision that if they wanted the cooperation of the conquered Japanese population, they needed the help of Emperor Hirohito to manage Japanese culture peacefully.While many military officials realized that Emperor Hirohito was involved in the planning and execution of Japanese aggression during World War II; they appreciated that trying him as a war criminal
would have alienated the Japanese population. Instead, the myth that Hirohito had been simply a "figurehead" who was manipulated and lied to by Japanese military officers, was carefully disseminated. Historian Herbert P. Bix has documented this in the book "Hirohito and the Making of Modern Japan," which is an excellent read on the real role that Hirohito played during World War II.