Which 1956 agreement formally ended Japan’s state of war with the Soviet Union?

The Soviet-Japanese Joint Declaration of 1956 formally ended Japan’s state of war with the Soviet Union.

The declaration was signed in Moscow on 19 October 1956 and took effect after ratification on 12 December. It restored diplomatic relations between the two countries and declared that the state of war would end once the agreement entered into force.

The arrangement followed a complicated postwar relationship. The Soviet Union had declared war on Japan in August 1945 and invaded Japanese-held territory in Manchuria, Korea, Sakhalin, and the Kuril Islands. Because the Soviet Union did not sign the 1951 Treaty of San Francisco, the two countries still needed a separate settlement.

The declaration did not resolve every territorial dispute. Japan and Russia continued to disagree over the southern Kuril Islands, known in Japan as the Northern Territories. A full peace treaty between the two countries has remained unsettled, even though diplomatic relations were restored in 1956.