Stalin ordered the invasion of Manchukuo on 9 August 1945, according to conditions of Tehran Conference and inaugurated in one of the largest campaigns in the Second World War.

The massive Red Army steamrolled into Manchuria, brushing aside scattered Japanese resistance, and occupied Mengjiang (Inner Mongolia), southern Sakhalin, and the northern half of the Korean peninsula as well.

The rapid defeat of the Kwantung Army in Manchuria, along with the recent atomic bombing of Hiroshima and Nagasaki by the Americans, contributed significantly to the Japanese surrender on the 15th.

On August 15, 1945, Emperor Hirohito announced Japan's unconditional surrender to the Japanese people over radio, marking the end of World War II.

The resumption of the Chinese Civil War in early 1946 prompted the Red Army to finish the withdrawal,[7] but not before secretly turning much of Manchuria over to the CCP in March in violation of the Agreement.