Occupation of Japan

Japan was occupied and administered by the Allies of World War II from the surrender of the Empire of Japan on September 2, 1945, at the war's end until the Treaty of San Francisco took effect on April 28, 1952. The occupation, led by the American military with support from the British Commonwealth and under the supervision of the Far Eastern Commission, involved a total of nearly one million Allied soldiers. The occupation was overseen by the US general Douglas MacArthur, who was appointed Supreme Commander for the Allied Powers (SCAP) by the US president Harry S. Truman; MacArthur was succeeded as supreme commander by General Matthew Ridgway in 1951. Unlike in the occupations of Germany and Austria, the Soviet Union had little to no influence in Japan, declining to participate because it did not want to place Soviet troops under MacArthur's direct command.

This foreign presence marks the only time in the history of Japan that it has been occupied by a foreign power. However, unlike in Germany, the Allies never assumed direct control over Japan's civil administration. In the immediate aftermath of Japan's military surrender, the country's government continued to formally operate under the provisions of the Meiji Constitution.

Furthermore, at General MacArthur's insistence, Emperor Hirohito remained on the imperial throne and was effectively granted full immunity from prosecution for war crimes after he agreed to replace the wartime cabinet with a ministry acceptable to the Allies and committed to implementing the terms of the Potsdam Declaration, which among other things called for the country to become a parliamentary democracy. Under MacArthur's guidance, the Japanese government introduced sweeping social reforms and implemented economic reforms that recalled American "New Deal" priorities of the 1930s under President Franklin D. Roosevelt. In 1947, a sweeping amendment to the Meiji Constitution was passed that effectively repealed it in its entirety and replaced it with a new constitution, and the Emperor's theoretically vast powers, which for many centuries had been constrained only by conventions that had evolved over time, became strictly limited by law as a constitutional monarchy.