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.

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.

[5] The occupation of Japan can be usefully divided into three phases: the initial effort to punish and reform Japan; the so-called "Reverse Course" in which the focus shifted to suppressing dissent and reviving the Japanese economy to support the US in the Cold War as a country of the Western Bloc; and the final establishment of a formal peace treaty with the 48 Allies of the Second World War and an enduring military alliance with the United States.

Under the final plan, however, Supreme Commander for the Allied Powers (SCAP) was to be given direct control over the main islands of Japan (Honshu, Hokkaido, Shikoku, and Kyushu) and the immediately surrounding islands, while outlying possessions were divided between the Allied Powers as follows: In early August 1945, with Japan's surrender seeming probable, the US Joint Chiefs of Staff recommended to President Harry S. Truman that Pacific Theatre Commander General Douglas MacArthur be named Supreme Commander for the Allied Powers (SCAP) to oversee the surrender and occupation of Japan.

In the end, despite its initial hopes, the Soviet Union did not manage to occupy any part of the Japanese home islands, largely due to significant U.S. opposition that was backed by the leverage gained by its then newly realized status as the world's only nuclear-armed state.

Moreover, whereas China, Korea and Japan were all a considerable distance from the USSR's European heartland, Stalin regarded establishing a powerful buffer against further military threats from the west to be vital to the Soviet Union's future existence.

Following the dropping of atomic bombs and the entry of the Soviet Union into the war against Japan, on the night of 9–10 August 1945, Emperor Hirohito announced his decision that the Japanese government should accept the terms demanded by the Allies in the Potsdam Declaration to Prime Minister Kantarō Suzuki and his administration.

By the beginning of 1946, replacement troops began to arrive in the country in large numbers and were assigned to MacArthur's Eighth Army, headquartered in Tokyo's Dai-Ichi building.

The air raids on Japan's urban centers left millions displaced, and food shortages (created by bad harvests and the demands of the war) worsened when the seizure of foodstuffs from Korea, Taiwan, and China ceased.

[36] Two days later, before any action was taken to enact the cabinet's decision, General MacArthur issued his five-point reform directive, one of the points being an order to liberate Japanese women through enfranchisement.

At SCAP's insistence, as part of a New Year's Day message, Emperor Hirohito publicly renounced his own divinity, declaring: The ties between Us and Our people have always stood upon mutual trust and affection.

[42] Included in the revised charter was the famous Article Nine, whereby Japan forever renounced war as an instrument of state policy and became forbidden to maintain a standing army.

[42] The 1947 Constitution also officially enfranchised women, guaranteed fundamental human rights, strengthened the powers of Parliament and the Cabinet, and decentralized the police and local government.

The Japanese writing system was drastically reorganized with the Tōyō kanji-list in 1946, predecessor of today's Jōyō kanji, and orthography was greatly altered to reflect spoken usage.

Before the war crimes trials actually convened, the SCAP, its International Prosecution Section (IPS) and Shōwa officials worked behind the scenes not only to prevent the imperial family from being indicted, but also to slant the testimony of the defendants to ensure that no one implicated the Emperor.

[50] Thus, months before the Tokyo tribunal commenced, MacArthur's highest subordinates were working to attribute ultimate responsibility for attack on Pearl Harbor to former prime minister Hideki Tojo[51] by allowing "the major criminal suspects to coordinate their stories so that the Emperor would be spared from indictment.

[54]The Reverse Course (逆コース, gyaku kōsu) is the name commonly given to a major shift in the Occupation policies that began in 1947 in response to the emerging global Cold War.

"[55] An early sign of the shift in SCAP's thinking came in January 1947 when MacArthur announced that he would not permit a massive, nationwide general strike that labor unions had scheduled for February 1.

[56] SCAP also attempted to weaken the labor unions they had recently empowered, most notably issuing an edict stripping public-sector workers of their right to go on strike.

It came into effect on April 28, 1952, formally ending all occupation powers of the Allied forces and restoring full sovereignty to Japan, except for the island chains of Iwo Jima and Okinawa, which the United States continued to hold.

[63] Since the end of the Occupation, the United States has continuously pressured Japan to revise its American-imposed constitution to remove Article 9 and fully remilitarize.

[69] Some historians have estimated that U.S. troops committed thousands of rapes among the population of the Ryukyu Islands during the Okinawa Campaign and the beginning of the American occupation in 1945.

According to John W. Dower, precisely as the Japanese government had hoped when it created the prostitution facilities, while the RAA was in place "the incidence of rape remained relatively low given the huge size of the occupation force.

It has been argued that the granting of rights to women played an important role in the radical shift Japan underwent from a war nation to a democratized and demilitarized country.

[81][83] In 1953, journalist Ichirō Narumigi commented that Japan had received "liberation of sex" along with the "four presents" that it had been granted by the occupation (respect for human rights, gender equality, freedom of speech, and women's enfranchisement).

The "modern girl" phenomenon of the 1920s and early 1930s had been characterized by greater sexual freedom, but, despite this, sex was usually not perceived as a source of pleasure (for women) in Japan.

[84] The sexual liberation of European and North American women during World War II was unthinkable in Japan, especially during wartime where rejection of Western ways of life was encouraged.

[83] In 1946, the 200 wives of U.S. officers landing in Japan to visit their husbands also had a similar impact when many of these reunited couples were seen walking hand-in-hand and kissing in public.

The really important duty of the so called Military government teams was, however, the supervision of the issue throughout Japan of the large quantities of food stuffs and medical stores being poured into the country from American sources.

The teams also contained so-called experts on health, education, sanitation, agriculture and the like, to help the Japanese in adopting more up to date methods sponsored by SCAP’s headquarters.