After World War II, the United States occupied and controlled Japan alone. On August 1945, Japan announced its unconditional surrender. The United States actively planned to occupy Japan alone, and Truman formally approved the memorandum on "occupation of the State Council and the military government" proposed by the Japanese, clearly stipulating that "multi-country division of occupation is not allowed" and that "the United States bears the main responsibility of providing the occupying forces, and the commander-in-chief of the occupying forces and his subordinate commanders should be Americans".

1945 August 15, after Japan announced its unconditional surrender, the U.S. government was prepared to appoint its supreme commander to occupy Japan on behalf of its allies without any consultation with them. After learning this news, the Soviet Union actively requested to participate in the occupation and control of Japan, and suggested to the American ambassador that when occupying Japan, the supreme commander could include Soviet-American generals Alexander Vasilevsky and MacArthur, but the US refused. The United States insisted that MacArthur be the supreme commander of the allied forces stationed in Japan alone.

1on August 3, 945, the United States informed its allies of the "Commander-in-Chief No.1" order issued to the Japanese government. It stipulated that "Japan, the Philippines and North Korea were surrendered by MacArthur, the supreme commander of the US Pacific Army, south of 38 degrees north latitude". Stalin basically agreed to the demands of the United States.

On August 28th, 1945, the first batch of American marines landed in Yokosuga, and then150,000 American troops occupied the whole territory of Japan and began to occupy Japan in the name of allied occupation forces. From August 30th to September 6th, a total of 460,000 American troops led by MacArthur successively entered Japan, taking control of major cities and strategic points. Because the Soviet Union refused to send troops under MacArthur's command, the Kuomintang government in China was too busy fighting the civil war to send occupation troops. Only New Zealand and Australia sent a small number of troops to join the occupying forces. On September 7, the "Allied Supreme Commander General Command" with the US as the main body was established. In addition to the General Staff Department, nine bureaus, including civil affairs, civil intelligence, economic science and natural resources, have been set up to fully control Japan's internal affairs. Although far eastern commission, composed of 1 1 countries, was established as the decision-making body above the Allied Supreme Commander, and the Allied Japanese Control Committee, composed of four representatives, was established as the advisory body, in fact, everything was decided by the Allied Supreme Commander General Command and MacArthur. The so-called allied occupation of Japan is only a form, but it is actually occupied and controlled by the United States alone.

1 On September 22nd, 945, the United States clearly stated in its policy toward Japan at the beginning of the occupation that the ultimate goal of American occupation of Japan was (1) to ensure that Japan would no longer pose a threat to world security and peace. (2) Finally, a peaceful and responsible government should be established, which should respect the rights of other countries and support the goals of the United States embodied in the ideals and principles of the United Nations Charter. This shows that safeguarding the interests of the United States has become the highest standard of American policy toward Japan.