SCAP named the Allied occupation authority governing Japan after its 1945 surrender.
SCAP stands for Supreme Commander for the Allied Powers, the title and headquarters associated with General Douglas MacArthur during the occupation. Although the abbreviation literally referred to the commander, it was also widely used for the occupation administration and its headquarters in Tokyo.
SCAP operated under Allied authority but was dominated by the United States. It supervised demilitarization, political reform, a new constitution, land reform, and changes to Japan’s education and economic systems. The occupation began after the surrender and continued until the San Francisco Peace Treaty came into force in 1952. SCAP should not be confused with the Allied Control Council in Germany or with the International Military Tribunal for the Far East, which prosecuted wartime leaders.