What title did Douglas MacArthur hold during the Allied occupation of Japan after the 1945 surrender?

Douglas MacArthur held the title Supreme Commander for the Allied Powers during the Allied occupation of Japan.

The position was created in August 1945 as the surrender process moved into occupation and demilitarization. MacArthur served as SCAP, an abbreviation for Supreme Commander for the Allied Powers, and directed the occupation from his headquarters in Tokyo. The title referred both to MacArthur’s authority and, in common usage, to the organization operating under his command.

SCAP supervised major political, legal, economic, and social changes in postwar Japan. Its directives helped demobilize the Japanese armed forces, reorganize government institutions, introduce land reform, and prepare the country’s postwar constitution. The occupation was led by the United States but involved personnel and forces from several Allied countries.

SCAP is sometimes confused with GHQ, or General Headquarters. In Japan, GHQ commonly referred to the occupation headquarters and its staff, while SCAP was the formal title of MacArthur and the authority issuing directives. The occupation formally ended in 1952 after the Treaty of San Francisco took effect.