Which 1951 treaty formally restored peace between Japan and most Allied countries after World War II?

The Treaty of San Francisco formally restored peace between Japan and most Allied countries after World War II.

Japan signed the treaty on September 8, 1951, at the San Francisco War Memorial Opera House. It entered into force on April 28, 1952, ending the Allied occupation and restoring Japan's sovereignty.

The treaty was separate from the Japanese Instrument of Surrender, which Japan signed in 1945 to end the fighting. The surrender ended active hostilities, while the later peace treaty established the formal postwar legal relationship between Japan and many former enemies.

The Soviet Union attended the conference but did not sign the treaty. Because some wartime disputes remained unresolved, Japan later made separate agreements with countries that were not parties to the San Francisco treaty. This is why the 1945 surrender and the 1951 peace settlement are treated as different milestones.