How Stalin Took Japan by Surprise in 1945

January 22, 2021 Topic: History Region: Asia Blog Brand: The Reboot Tags: World War IISoviet UnionJapanManchuriaChina

How Stalin Took Japan by Surprise in 1945

Reeling from two atomic bombs, the Japanese were physically and psychologically un-prepared for a massive invasion from communist Russia.

Here's What You Need to Know: Stalin had his own agenda, and Soviet participation in the Far East was at the top of his list.

At 11:02 am on August 9, 1945, an American warplane dropped an atomic device nicknamed “Fat Man” onto the city of Nagasaki, Japan. The bomb, generating the explosive power of 22,000 tons of TNT, killed at least 30,000 people instantly. It was the second of two atomic bombs dropped in three days’ time on Japan by an American government intent on forcing the aggressor nation’s unconditional surrender and hastening an end to World War II. But it was also the day that the Soviet invasion of Manchuria officially began. 

Since the previous midnight, Soviet armies numbering over a million men, backed by armored, air, and naval forces, had begun sweeping into Manchuria—the Japanese puppet state on the East Asian mainland that the occupiers called Manchukuo—in what would be the last great military operation of World War II. The Soviet assault, a classic double-pincer movement with attacks from the west, north, and east, extended across water and land fronts some 2,730 miles from the Mongolian desert to the densely forested coast of the Sea of Japan. (You can read more about the Soviet Union’s involvement in the Second World War, including the bitter fighting across the Eastern Front, inside the pages of WWII History magazine.) 

“The Scale of These Attacks is Not Large”

After bewildered Japanese units on the Manchurian border were hit with heavy shelling and massive ground assaults in the early morning hours of August 9, Japan’s Imperial headquarters issued an emergency announcement reporting that the Soviet Union had declared war on Japan and had begun entering Manchurian territory, but added absurdly, “The scale of these attacks is not large.” In reality, the first elements of a 1.5-million-man Soviet host, backed by small cavalry units of its ally, Outer Mongolia, were already in motion. Infantry, tank, horse cavalry, and mounted infantry, supported by river flotillas, air fleets, and 4,300 Soviet planes, would commence the invasion by striking Japanese convoys and cities in Manchuria and North Korea.

The Soviet Pacific Fleet stood ready to carry the invasion to the islands north of Japan—Sakhalin and the Kurils—which czarist Russia had lost to the Japanese 40 years earlier, along with the lease to the strategic warm-water port of Port Arthur, at the end of the Russo-Japanese War in 1905. For Soviet leader Joseph Stalin, the time had come to gather as much Asian booty as possible, while also erasing some of the stain remaining from the devastating, unexpected 1905 defeat—the first time an emerging Asian power had defeated a European power in the modern era.

As Nazi Germany’s continuing conquests in Europe threatened to spread the war to other continents and turn the conflict into another true global war, the Japanese and Russians in April 1941 concluded a five-year neutrality pact that served the interests of both nations well. Japan’s expansionist ambitions lay to the south and east, and it needed to guard against a threat from the rear. Russia, even before Japan found itself in a life-and-death struggle along with Nazi Germany, desired no complications in Asia. When the Germans invaded Russia in June 1941, Stalin, assured his eastern flank was secure, safely threw all his resources into the war in the West. Indeed, until August 8, 1945, Soviet neutrality in the East was so scrupulously preserved that American B-29 bombers that force-landed on Russian territory during raids on Japan had to remain there.

The Strangulation of Japan by American Blockade

Although peace on the Russian-Manchurian border continued to suit the two neighbors well, by 1944 it no longer suited the United States. There were more than a million Japanese soldiers in Manchuria and eastern China who could be redeployed against the Allies at any time. An invasion of Manchuria by the Russians was the obvious means of deflecting such a threat. In December 1944, after almost three years of massive efforts by the United States, including the employment of a quarter-million Americans on the Asian mainland supplying and advising Chiang Kai-shek’s Nationalist Army in its futile operations against the Japanese, U.S. commanders concluded that Japan’s forces in Asia could not be defeated by the Chinese.

Neither Chiang’s Kuomintang Army, nor Mao Zedong’s Communist guerrilla forces mounted even the most minimal opposition to Japanese occupiers. Both organizations were clearly more interested in what would happen after the war ended and the Japanese were driven from the Asian mainland. Washington therefore turned to the only other power capable of defeating the Japanese—the Soviet Union. Throughout the winter of 1944-1945, with increasing urgency, Washington solicited Russian participation in the war against Japan. American field commanders wanted all the help they could get to diminish the numbers of Japanese they would have to confront in the climactic battles in the Pacific Theater. Great Britain’s prime minister, Winston Churchill, and American President Franklin D. Roosevelt were heartened by Stalin’s promise to launch 60 Soviet divisions against Japan within three months of Germany’s collapse.

Washington realized that the Russians wouldn’t fight unless they received tangible rewards for doing so. To destroy the Nazis, the Soviets had already contributed 25 times the human sacrifice made by all the other Allies combined. At a conference at Yalta in early February 1945, Stalin presented his demands for an eastern commitment: the Kuril Islands (a mostly uninhabited chain that ran from Russia’s Kamchatka Peninsula to the northernmost tip of the Japanese home island of Hokkaido), southern Sakhalin Island, the lease of Port Arthur, access to Dalian as a free port, control of the southern Manchurian railway, and recognition of Soviet suzerainty over Outer Mongolia. On February 8, the fifth day at Yalta, Roosevelt agreed to Stalin’s terms; by doing so, he made important Chinese territorial commitments without first consulting the Chinese. The agreements were nominally subject to Chiang Kai-shek’s endorsement, in return for which Moscow pledged to recognize the Nationalists as China’s sole legitimate rulers.

By June 1945, after a three-month bloodbath secured the island of Okinawa—the final stepping-stone to a land invasion of Japan—American commanders welcomed any alternative that would avert the necessity of a ground assault. The prospect of using atomic weapons against the Japanese didn’t yet loom in their minds; their hopes of achieving victory without launching an amphibious invasion of Japan rested upon blockade, incendiary aerial bombardment, and Russian entry into the war. In the weeks to come, the successful testing of an atomic weapon on July 16 made the new American president, Harry Truman, far less enthusiastic about Russian intervention and expansionism in Asia.

Japan was slowly being strangled by an economic blockade that had brought her war-making capacity almost to a halt. In addition, beginning with the horrific firebombing of Tokyo on March 9, General Curtis LeMay’s conventional bomber force was in the process of virtually destroying Japan. B-29 bombers flying from the Mariana Islands had already leveled most of Japan’s major cities, killing some 200,000 civilians. By mid-1945, all these factors rendered an Allied invasion of the Japanese mainland increasingly unnecessary, and to some American political leaders the Soviet invasion of Manchuria seemed superfluous. Stalin had his own agenda, however, and Soviet participation in the Far East, agreed upon at Yalta, was at the top of his list.

The Soviet Far East Command

Their initial response to the August 9 invasion showed once again that the Japanese were either grossly unaware, or simply refused to accept, the direness of their predicament. Even those in Tokyo who had accepted that Stalin was “waiting for the ripe persimmon to fall,” and who had been repeatedly warned of Soviet troop movements eastward, had concluded that the Russians wouldn’t be ready to attack in Manchuria until autumn or the spring of 1946.

Inside Manchuria, Japan’s Kwangtung Army, commanded by General Otozo Yamada, was nowhere near operational readiness; its best units had been sent to Okinawa and Kyushu months earlier. Few demolition charges had been laid, air support was negligible, and some senior commanders were absent from their posts. In the early months of 1945, tens of thousands of refugees from the Japanese home islands had moved to Manchuria with all their possessions, believing the colony to be a safe haven. Incredibly, no steps were taken to evacuate these Japanese civilians, on the grounds that such precautions would promote defeatism. Stalin’s objective was massive territorial gain, and he was prepared to pay heavily for it. For the Manchurian invasion, the Soviets made medical provisions for 540,000 casualties, including 160,000 dead (a forecast predicated on an assessment of Japan’s paper strength). Stalin had for years maintained 40 divisions on the Manchurian border, and in the spring of 1945 he doubled his forces there. Between May and June, some 3,000 locomotives labored tirelessly along the Trans-Siberian rail link, transferring an additional 40 Soviet divisions on a month-long journey eastward to the Mongolian and Manchurian borders.

After traveling 6,000 miles from Europe by rail, Soviet units marched the last 200 miles to the Manchurian border across the treeless Mongolian desert in blazing heat. As part of Stalin’s agreement with the Allies, the United States helped feed and arm the Soviet host; some 500 new Sherman tanks were offloaded at Russian ports. As Russian troops approached the frontier, elaborate camouflage and deception schemes were adopted; senior Soviet officers traveled under false names and didn’t wear rank insignia. The 6th Guards Tank Army left all its tanks, self-propelled artillery, and vehicles in Czechoslovakia, picking up new equipment manufactured by the Soviet Ural factories.