The Manchurian Strategic Offensive Operation began on 9 August 1945 with the Soviet invasion of the Japanese puppet state of Manchukuo. It was the last campaign of the Second World War; and the largest of the 1945 Soviet-Japanese War which resumed hostilities between the Soviet Union and the Empire of Japan after almost six years of peace.

Temporary Soviet gains on the continent were Manchukuo; Inner Mongolia and northern Korea. The Soviet entry into the war and the defeat of the Kwantung Army was a significant factor in the Japanese government's decision to surrender.