Excerpts from Books and Wikipedia
"On April 28, 1952, the San Francisco Peace Treaty, the Japan-U.S. Security Treaty, and the Administrative Agreement granting American military forces in Japan special privileges all went into effect simultaneously. GHQ [General Headquarters] was abolished; the occupation ended. Thousands of American armed forces began to go home. Japan now, at last, regained formal independence." [Hirohito, p. 647]