Which Soviet operation began on 9 August 1945 as Japan faced surrender?

The Manchurian Strategic Offensive Operation began on 9 August 1945 as Japan faced surrender.

Also called the Soviet invasion of Manchuria and, in some Western accounts, Operation August Storm, it attacked Japanese forces in Manchuria, Inner Mongolia, and northern Korea. The Soviet Union launched the offensive after declaring war on Japan, breaking the Soviet-Japanese Neutrality Pact.

The attack struck the Kwantung Army, which had once been Japan's most powerful field army but had been weakened by transfers to other fronts. Soviet forces used coordinated attacks from multiple directions, rapidly overrunning Japanese positions and dismantling Japan's control of Manchukuo. The campaign continued even after Japan's public surrender announcement, and the Kwantung Army formally surrendered on 16 August.

Historians debate the relative weight of the Soviet entry and the atomic bombings in Japan's decision to capitulate. Both developments shattered Japanese hopes of negotiating through Moscow and intensified the crisis in Tokyo. The offensive ended officially on 2 September, the day the surrender document was signed.