Key Facts
- Start date
- 9 August 1945
- Kwantung Army surrender
- 16 August 1945
- Final cessation of fighting
- 2 September 1945
- Soviet withdrawal from Manchuria
- 3 May 1946
- Soviet occupation of northern Korea
- Until 1948
- Soviet occupation of Port Arthur
- Until 1955
Strategic Narrative Overview
Soviet forces launched a massive coordinated offensive across Manchuria and Inner Mongolia simultaneously with the atomic bombing of Nagasaki. The Kwantung Army, weakened by transfers to other fronts, was rapidly overwhelmed. Soviet naval forces also launched amphibious assaults capturing northern Korea. The combination of the atomic bombings and the Soviet offensive's swift success left Japan's military position untenable, prompting the emperor's decision to surrender by 15 August.
01 / The Origins
After nearly six years of uneasy peace, the Soviet Union entered the war against Japan on 9 August 1945, fulfilling commitments made to the Western Allies at Yalta. Japan had hoped the USSR would broker a negotiated conditional surrender, but the Soviet declaration of war shattered that strategy. The invasion targeted Japan's puppet states of Manchukuo and Mengjiang, aiming to eliminate the Kwantung Army and extend Soviet influence in East Asia.
03 / The Outcome
Japan formally surrendered on 2 September 1945 when the Japanese Instrument of Surrender was signed. The Soviet Union occupied Manchuria, Inner Mongolia, and northern Korea, signing the Sino-Soviet Treaty of Friendship with the Kuomintang. Red Army withdrawal from Manchuria by May 1946 effectively handed the region to Chinese Communist forces, shaping the outcome of the Chinese Civil War. Scientists from Unit 731 were tried at the 1949 Khabarovsk war crimes trials.
Belligerents & Mobilization Analysis
Side A
1 belligerent
Aleksandr Vasilevsky.
Side B
3 belligerents
Kinetic Engagement Axis
Scroll horizontally to view full axis. Events plotted relatively.