What nickname is sometimes given to the Soviet invasion of Manchuria that began on August 9, 1945?

Operation August Storm is a nickname sometimes given to the Soviet invasion of Manchuria that began on August 9, 1945.

The Soviet Union declared war on Japan on August 8 and launched its invasion just after midnight on August 9. Soviet forces attacked Japanese-held Manchuria from multiple directions, while also advancing into areas including Inner Mongolia and northern Korea. The campaign is more formally associated with the Manchurian Strategic Offensive Operation.

The offensive rapidly overwhelmed the Japanese Kwantung Army, which had previously been regarded as a major Japanese force. Its defeat removed Japan's hope that the Soviet Union might mediate a conditional peace with the Western Allies. The Soviet entry therefore became one of the major pressures surrounding Japan's decision to surrender.

“Operation August Storm” is a later Western nickname rather than the principal Soviet wartime designation. It should not be confused with Operation Downfall, the proposed Allied invasion of Japan's home islands, which was never carried out.