Bombing of Hiroshima and Nagasaki and the Japanese Surrender

FROM THE LECTURE SERIES: The Rise of Modern Japan

Mark J. Ravina, University of Texas at Austin

The US stopped aerial assaults on Hiroshima in May 1945 so that the impact of an atomic bomb would be measurable. Then what exactly convinced Japan to surrender on August 15, 1945? Was it the atomic bombing on Hiroshima on August 6, or the second one on Nagasaki on August 9, or something more? Read on to find out.

A photograph of Winston Churchill, Franklin Roosevelt, and Joseph Stalin.
Joseph Stalin (far right) had committed to his Allied partners—the United States and Britain—at the Yalta Conference in Crimea, that it would also attack Japan. (Image: US government photographer/Public domain)

The Soviet Union

Standard accounts of the Japanese surrender focus, unsurprisingly, almost entirely on the United States. Yet, there could have been many more contributing factors. One of them being the Battle of Okinawa in April, May, and June 1945 that broke the emperor’s confidence in his own military. Conventional airpower could have been the other, which reduced major Japanese cities to rubble.

And then, there’s the elephant in the room, the Soviet Union. The Soviets attacked Japan with overwhelming force beginning hours before the second bomb dropped on Nagasaki on August 9.

Joseph Stalin

The Soviets swept through Manchuria, crushing exhausted Japanese troops, and capturing tens of thousands of prisoners of war. They swept down the Kuril Islands, so that the invading force gained a guard post less than four miles from Japan proper.

Soviet leader Joseph Stalin even considered seizing part of Hokkaidō, Japan’s second-largest island, until Franklin Roosevelt’s successor, President Harry Truman, pushed back hard.

The Yalta Conference

Why did the Soviets attack? Well, in February 1945, Stalin had committed doing so to his Allied partners—the United States and Britain—at the Yalta Conference in Crimea.

He promised Roosevelt and British Prime Minister Winston Churchill that the USSR would attack Japan “two or three months” after the surrender of Nazi Germany.

In return, the Soviets were promised Manchuria, the southern half of Sakhalin Island, and the Kuril Islands. Russia, by the way, had ceded the Kuril Islands to Japan back in 1875.

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Truman and Stalin at Potsdam

Subsequently, at a meeting between Truman and Stalin at Potsdam, Germany, in late July 1945, Truman concluded that the Soviets would enter the war against Japan that August. But by that time, the United States was becoming much less enthusiastic about working with Stalin.

The United States excluded the Soviets from the Potsdam Declaration of July 26, 1945, which called for Japan’s surrender. It was issued in Truman’s name for the United States, Churchill’s for the United Kingdom, and Chiang Kai-shek’s for China. Stalin was left out.

An image of a mushroom cloud over Hiroshima.
The atomic bomb at Hiroshima demonstrated that the United States could obliterate Japanese cities with impunity. (Image: Everett Collection/Shutterstock)

The Atomic Bomb at Hiroshima

Stalin began to worry that the United States would renege on promises made at Yalta. Further, after the United States dropped the first atomic bomb at Hiroshima, Stalin realized he would have to strike hard and fast, or Japan might surrender before Russia got all the territory it had been promised.

The atomic bomb at Hiroshima demonstrated that the United States could obliterate Japanese cities with impunity. And it prompted Stalin to enter the war with massive force, confronting the Japanese government with terrifying prospect of surrendering to the Soviet Union.

The Japanese emperor dismissed prime Minister Konoe Fumimaro’s warnings about fighting a losing battle that February, but by August, they seemed prophetic.

Nagasaki

Thinking along those lines, the second atomic bomb at Nagasaki becomes even more morally problematic; much more troubling than Hiroshima.

Unlike Hiroshima, Nagasaki had little value as a military target. And there’s little evidence that Japanese leaders had processed the scale of the Hiroshima bombing in just three days.

Nagasaki, one would argue wasn’t one of the last bombs of WWII but among the first of the Cold War: a signal from Truman to Stalin to not get greedy and go beyond the territory promised at Yalta. Hence, the Cold War began before World War II was over.

Konoe Fumimaro

So what happened to Konoe in the postwar world? Well, he’s an impossibly tragic figure. The US occupying force briefly tapped him as an adviser on drafting a new postwar constitution. He had, of course, advocated an early end to the war.

Then, it was decided that he was a war criminal. Which was also true: Konoe had plunged Japan into a war in China in 1937. Racked by guilt and fearful of the future, Konoe decided not to wait for the US occupation to decide his fate. He took cyanide and died by suicide on December 16, 1945.

Common Questions about the Bombing of Hiroshima and Nagasaki and the Japanese Surrender

Q: Why did the Soviet Union invade the Kuril Islands?

The Soviets swept through Manchuria, crushing exhausted Japanese troops, and capturing tens of thousands of prisoners of war. They swept down the Kuril Islands, so that the invading force gained a guard post less than four miles from Japan proper.

Q: In whose name was the Potsdam Declaration issued?

The Potsdam Declaration of July 26, 1945, called for Japan’s surrender. It was issued in Harry Truman’s name for the United States, Winston Churchill’s for the United Kingdom, and Chiang Kai-shek’s for China. The United States excluded the Soviets from it, thus Joseph Stalin was left out.

Q: What purpose did the Hiroshima bomb serve for the United States and the Soviet Union?

The atomic bomb at Hiroshima served a dual purpose. It demonstrated that the United States could obliterate Japanese cities with impunity. And it also prompted Stalin to enter the war with massive force, confronting the Japanese government with terrifying prospect of surrendering to the Soviet Union.

Keep Reading
The Bloody Events of the Russo-Japanese War
The Creation of the Atomic Bomb
The Causes of the Russo-Japanese War: From Imperialism to War