The Supreme Commander for the Allied Powers (SCAP) (originally briefly styled Supreme Commander of the Allied Powers[1]) was the title held by General Douglas MacArthur during the Allied occupation of Japan following World War II.
In Japan, the position was generally referred to as GHQ (General Headquarters), as SCAP also referred to the offices of the occupation, including a staff of several hundred U.S. civil servants as well as military personnel. Some of these personnel effectively wrote a first draft of the Japanese Constitution, which the National Diet then ratified after a few amendments. Australian, British, Indian, and New Zealand forces under SCAP were organized into a sub-command known as British Commonwealth Occupation Force.
My dad was part of those occupation forces in Japan immediately following WWII, as a Master Sergeant. He was in charge of seeing to the needs of a large neighborhood in Tokyo of thousands of Japanese. While there, he lived in a mansion, and had a driver with a big car, lived good until he left for the states in 1949. Two of my older sisters were born there. Tokyo was a wreck, and people were starving. Good ole Americans got things working again and helped the people, what other conquerer does that? Anyway, Dad got a personal commendation from MacArthur. Didn't talk much about the war, but I have a few pictures of him at the mansion in Tokyo from the time.