What was the Western codename for the Soviet invasion of Japanese-occupied Manchuria in August 1945?

Operation August Storm was the Western codename for the Soviet invasion of Japanese-occupied Manchuria in August 1945.

The offensive began on August 9, 1945, after the Soviet Union declared war on Japan. Soviet forces attacked the Japanese puppet state of Manchukuo from several directions, while other operations extended into Inner Mongolia, southern Sakhalin, and northern Korea. The campaign is also formally called the Manchurian Strategic Offensive Operation.

The invasion overwhelmed the Kwantung Army, Japan's principal force in Manchuria. Its timing was crucial: it began between the atomic bombings of Hiroshima and Nagasaki and removed Japan's hope that the Soviet Union might mediate a conditional peace.

Operation August Storm is not the same as Operation Downfall, the proposed Allied invasion of Japan, or Operation Olympic, the planned invasion of Kyushu. Japan announced its surrender on August 15, although fighting in some areas continued until September.