Soviet Invasion of Manchuria (1945): Operation August Storm

The Soviet invasion of Manchuria, known in the Soviet Union as the Manchurian Strategic Offensive Operation and in the West as Operation August Storm, began on 9 August 1945. More than 1.5 million Soviet troops attacked Japanese-held north-east China from three directions and defeated the Kwantung Army in about ten days.

Coming in the same week as the atomic bombings of Hiroshima and Nagasaki, the Soviet entry into the war against Japan was one of the shocks that led to Japan’s surrender. It also reshaped the balance of power in East Asia, from China to the Korean peninsula.

Background

Japan had controlled Manchuria since the Mukden Incident of 1931 and ruled it through the puppet state of Manchukuo, with the last Qing emperor, Puyi, as its nominal head. Its garrison, the Kwantung Army, had once been Japan’s elite force, and border clashes with the Soviet Union, notably at Khalkhin Gol in 1939, had ended in Japanese defeats.

In April 1941 Japan and the USSR signed a five-year neutrality pact, which allowed both to concentrate elsewhere. At the Yalta Conference in February 1945, however, Stalin promised to enter the Pacific war within two to three months of Germany’s surrender. In return he was promised southern Sakhalin, the Kuril Islands and rights in Manchurian ports and railways lost after the Russo-Japanese War. The Soviet Union announced on 5 April 1945 that it would not renew the neutrality pact.

The two sides

After Germany’s defeat, the Soviets moved huge forces east along the Trans-Siberian Railway. Under the overall command of Marshal Aleksandr Vasilevsky, three fronts were assembled: the Transbaikal Front under Marshal Rodion Malinovsky in the west, the 1st Far Eastern Front under Marshal Kirill Meretskov in the east, and the 2nd Far Eastern Front under General Maksim Purkayev in the north. Mongolian troops fought alongside them.

The Kwantung Army, commanded by General Otozō Yamada, had been stripped of many of its best units and much of its equipment to reinforce the Pacific and the home islands. Many of its divisions were newly raised, short of training, artillery and anti-tank weapons. Japanese planners expected that any Soviet attack would come later in the year and intended to withdraw to a defensive redoubt in the south-east of Manchuria near the Korean border.

The offensive

The Soviet Union declared war on Japan on the evening of 8 August, Moscow time, and attacked shortly after midnight on 9 August, local time. Hours later, the United States dropped an atomic bomb on Nagasaki.

The boldest thrust came from the west. Malinovsky’s Transbaikal Front, led by the 6th Guards Tank Army, crossed the edge of the Gobi Desert and the Greater Khingan Mountains, terrain that Japanese planners had considered nearly impassable for large armoured forces. Within days Soviet tanks were deep in the central Manchurian plain. In the east, Meretskov’s troops broke through heavily fortified border zones, while forces from the north crossed the Amur and Ussuri rivers.

Japanese units fought hard in some places, including at Mudanjiang, but they were outmanoeuvred, cut off and short of supplies. Soviet airborne detachments landed at key cities such as Harbin, Changchun and Mukden (Shenyang) in the final days to take control.

Why the Soviets advanced so fast

The speed of the campaign reflected careful planning. Soviet commanders drew on four years of experience against the German army and used it against an opponent that had not fought a modern mechanised war on this scale. They massed tanks, artillery and supply columns in secret, moving many units by night, so that Japanese intelligence underestimated both the size of the build-up and its timing.

The Soviets also chose to attack across terrain the Japanese thought unsuitable, such as desert and mountain passes, where defences were thin. Mobile forward detachments, small combined groups of tanks, motorised infantry and engineers, raced ahead of the main armies to seize passes, bridges and road junctions before Japanese units could react.

The Kwantung Army, by contrast, had few modern tanks or anti-tank guns, weak air support and poor communications. Many of its soldiers were reservists or recent conscripts. Its plan to fall back to the south-east was overtaken by events, leaving units scattered and isolated.

Surrender and wider operations

Emperor Hirohito announced Japan’s acceptance of the Allied terms on 15 August, but orders reached the front slowly and fighting continued. The Kwantung Army headquarters ordered a ceasefire on 17 August, and Soviet and Japanese commanders arranged its surrender over the following days. Puyi was captured by Soviet troops at Mukden airfield on 19 August as he tried to flee to Japan. Most organised resistance ended around 20 August.

Alongside Manchuria, Soviet forces landed in northern Korea, took southern Sakhalin from 11 August, and invaded the Kuril Islands from 18 August, where the battle for Shumshu was one of the hardest of the campaign. The Kurils were occupied by early September, after Japan’s formal surrender on 2 September.

Casualties

Official Soviet figures record about 12,000 Soviet soldiers killed and around 24,000 wounded. Japanese military deaths are less certain; estimates range from about 21,000 to over 80,000. Roughly 600,000 Japanese soldiers were taken prisoner.

Japanese civilian settlers in Manchuria suffered greatly. Abandoned by the retreating army, many died during flight, from violence, hunger and disease, or in the harsh winter of 1945–1946. Estimates of Japanese civilian deaths in Manchuria in this period are commonly around 180,000 to over 200,000.

Consequences

Most Japanese prisoners were sent to labour camps in Siberia, Central Asia and elsewhere in the USSR, where tens of thousands died; most survivors returned by 1950. The Soviets stripped Manchuria of much of its industrial equipment as war booty and handed captured Japanese weapons to Chinese Communist forces before withdrawing in 1946, a factor in the Communist victory in China’s civil war.

In Korea, the United States and the Soviet Union agreed to divide the peninsula at the 38th parallel to accept the Japanese surrender. This temporary line became the boundary between North and South Korea and the background to the Korean War. The Soviet occupation of the southern Kurils created a territorial dispute with Japan that remains unresolved.

The surrender debate

Historians continue to debate what ended the war. The traditional view in the United States emphasised the atomic bombs. Others, notably Tsuyoshi Hasegawa, argue that the Soviet attack was at least as decisive, because Japanese leaders had hoped the USSR would mediate a negotiated peace and because it threatened a Soviet role in occupying Japan. Most scholars now see both shocks as working together.

Timeline

• 1941, 13 April: Japan and the Soviet Union sign a neutrality pact.
• 1945, 11 February: At Yalta, Stalin agrees to enter the war against Japan.
• 1945, 5 April: The USSR announces it will not renew the neutrality pact.
• 1945, 8 August: The Soviet Union declares war on Japan.
• 1945, 9 August: Soviet forces invade Manchuria; Nagasaki is bombed.
• 1945, 15 August: Emperor Hirohito broadcasts Japan’s acceptance of surrender.
• 1945, 18 August: Soviet landings begin in the Kuril Islands.
• 1945, 19 August: Puyi is captured at Mukden.
• 1945, 20 August: Most organised resistance in Manchuria ends.

Why it matters

The Soviet invasion of Manchuria was one of the largest and fastest campaigns of the Second World War. It helped bring about Japan’s surrender, led to the division of Korea, aided the Communist rise in China and left a territorial dispute that still affects Russian–Japanese relations.