Although studied less often than the Nuremberg trials, the prosecution of Japanese war criminals after World War II was a major undertaking. The United States and its European allies tried 5,707 people; 4,524 were found guilty. (Few data are available regarding people prosecuted by the Chinese and the Soviets.) This legal and political history explores with exemplary nuance and clarity how the Allies handled difficult issues, such as the boundaries of necessary violence in war and the limits of command responsibility, thus forging new precedents for international law. It also shows how attitudes toward the trials changed as Japan became a Western ally during the Cold War, leading to the release of all Japanese prisoners by the late 1950s. For several reasons, the trials did not produce the kind of acceptance of historical guilt among Japanese that the trials of Germans yielded in Germany. The Japanese were less inclined to view their actions as unprovoked aggression, because many thought the West had started the conflict when it tried to strangle Japan’s access to resources. The Japanese had not committed ethnic genocide, so they were tried only for the kinds of crimes that the Allies themselves had committed before or during the war, leading many to see the trials as victors’ justice.