The Kwantung Army was the Soviet Union’s main opponent in the August 1945 invasion of Manchuria.
The Kwantung Army was Japan’s major military formation in Manchuria, the region Japan controlled through the puppet state of Manchukuo. On August 9, 1945, Soviet forces launched a massive offensive against Japanese positions from several directions. The operation rapidly overwhelmed the Kwantung Army and seized large areas of Japanese-held territory.
The force had once been regarded as an elite Japanese army, but by 1945 many experienced units and weapons had been transferred to other fronts. Its remaining formations were therefore less capable than the army’s earlier reputation suggested.
The Soviet offensive was one of the major events influencing Japan’s decision to surrender. Japanese leaders faced the Soviet attack at the same time as the atomic bombings of Hiroshima and Nagasaki and the continuing Allied demand for unconditional capitulation.