What marked the end of militarism in Japan post World War II was the adoption of the constitution in 1947, which included Article 9. This article explicitly renounced war and prohibited Japan from maintaining military forces for warfare. Following its defeat in World War II, Japan underwent significant political and social reforms under the Allied Occupation, particularly led by General Douglas MacArthur. The constitution established democratic governance and civil liberties, and Japan shifted its focus towards peace and reconstruction, marking a departure from its militaristic past and paving the way for its post-war economic recovery.