Short answers, pulled from the story.
The formal surrender ceremony took place on the 2nd of September 1945 aboard the USS Missouri in Tokyo Bay. General Douglas MacArthur signed the document ending World War II in Asia before representatives from Japan and the Allied Powers.
Supreme Commander for the Allied Powers held direct control over the main islands including Honshu Hokaido Shikoku and Kyushu. The United States maintained authority while outlying territories were distributed to other powers like the Soviet Union and China.
The Treaty of San Francisco came into effect on the 28th of April 1952 formally ending all Allied occupation powers. This event restored full sovereignty to Japan except for Iwo Jima and Okinawa which remained under U.S. control until later dates.
Universal suffrage was achieved in the first post-war election on the 10th of April 1946 with a voter turnout rate of 66.97% among women. This election brought Shigeru Yoshida into office as prime minister succeeding Kijūrō Shidehara on the 22nd of May 1946.
A major policy shift known as the Reverse Course began in 1947 responding to emerging Cold War tensions. U.S. priorities moved from punishing Japan to ensuring internal political stability rebuilding the shattered economy and remilitarizing Japan to support Western Bloc objectives in East Asia.