The Treaty of San Francisco restored Japan’s sovereignty on April 28, 1952, when it came into force.
The treaty was signed in San Francisco on September 8, 1951, by Japan and 48 Allied nations. It formally ended the state of war between Japan and most of the Allied powers and provided the legal framework for ending the Allied occupation. Its effective date, April 28, 1952, is therefore separate from Japan’s 1945 surrender ceremony.
The treaty required Japan to recognize the independence of Korea and renounce claims to Taiwan, the Pescadores, the Kuril Islands, and other territories. The Soviet Union attended the conference but did not sign the treaty. China was also not a signatory because of the political division between the Republic of China and the People’s Republic of China.
A frequent mistake is to treat the 1945 surrender as the date Japan regained full sovereignty. The surrender ended hostilities, while the Treaty of San Francisco ended the occupation framework and took effect nearly seven years later.