The
Manchurian Strategic Offensive Operation (, lit.
Manchzhurskaya Strategicheskaya Nastupatelnaya Operaciya) began on 9 August 1945, with the
Soviet invasion of the Japanese
puppet state of
Manchukuo and 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. Soviet gains on the continent were Manchukuo,
Mengjiang (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 unconditionally, as it made apparent the USSR would no longer be willing to act as a third party in negotiating an end to hostilities on conditional terms.