Soviet invasion of Manchuria

The Soviet invasion of Manchuria, formally known as the Manchurian Strategic Offensive Operation or simply the Manchurian Operation (Маньчжурская операция) and sometimes, mainly in the West, as Operation August Storm, began on 9 August 1945 with the Soviet Union's invasion of the Empire of Japan's puppet states of Manchukuo and Mengjiang, in Japanese-occupied Manchuria and Inner Mongolia respectively. It was the largest campaign of the 1945 Soviet–Japanese War, which resumed hostilities between the Union of Soviet Socialist Republics and the Empire of Japan after almost six years of peace.

Source: Wikipedia — Soviet invasion of Manchuria (CC BY-SA 4.0)