Ending the Deadliest Conflict in Human History: Why Did Japan Surrender in World War II?

Photo Credit: MPI / Getty Images
Photo Credit: MPI / Getty Images

The Japanese surrender in World War II brought to a close one of the darkest and deadliest chapters in human history. While the Germans waved the white flag in May 1945, it took the Empire of Japan several more months to admit they’d been defeated. Most believe the atomic bombings of Hiroshima and Nagasaki were the only reason the country surrendered, but, in reality, there were several factors at play.

Atomic bombings of Hiroshima and Nagasaki

Aerial view of Hiroshima, Japan
Ruins of Hiroshima following the atomic bombing, 1945. (Photo Credit: Universal History Archive / Universal Images Group / Getty Images)

Two key events that led to Japan’s surrender were the atomic bombings on Hiroshima and Nagasaki. On the morning of August 6, 1945, the former was subjected to an attack that decimated the city and inflicted a devastating human toll, with between 90,000-146,000 killed both during Little Boy‘s detonation and after, due to the effects of radiation exposure and burns to the skin.

Just three days later, on August 9, Nagasaki experienced a similar fate, with the Boeing B-29 Superfortress Bockscar dropping the atomic bomb Fat Man on the city, located some 261 miles from Hiroshima. Just like the latter, Nagasaki suffered extensive losses, with between 60,000-80,000 citizens perishing within four months of the attack.

Between both detonations, it’s estimated around 129,000-226,000 people lost their lives – a truly devastating number.

The atomic bombs not only demonstrated the US military’s superiority, but also signalled the emergence of a new and terrifying era in warfare. The realization that further nuclear attacks could obliterate Japanese cities forced leadership to reconsider their position; the fear of additional devastation, coupled with the understanding that conventional defenses were futile against such power, significantly influenced Japan’s decision to surrender.

Declaration of war by the Soviet Union

Soviet military tanks driving single-file through a valley
Soviet tanks advancing during the invasion of Manchuria, 1945. (Photo Credit: Sovfoto / Universal Images Group / Getty Images)

Compounding the despair following the atomic bombings, the Soviet Union’s declaration of war against Japan on August 8, 1945, dealt yet another severe blow to the Japanese military’s hopes. Officials hadn’t believed the Red Army to be much of a threat, with it assumed the Imperial Japanese Army (IJA) wouldn’t have to face Joseph Stalin‘s soldiers until Spring 1946. Emperor Hirohito had also previously requested the Soviet dictator act as an intermediary between Japan and the United States.

As a result, the Japanese military and Hirohito were shocked by the sudden Soviet invasion of Manchuria, which saw 650 of the 850 troops occupying the region killed or wounded in the first two days of combat. This declaration of war by the Soviet Union eradicated any hope Japan had for a mediated peace and highlighted the nation’s growing geopolitical isolation.

Faced with the prospect of a two-front war, Japanese leaders recognized the futility of their situation – Hirohito himself even begged military officials to reconsider a surrender.

Japan’s military resources were beginning to dwindle

Aerial view of the remnants of Tokyo, Japan
Remnants of Tokyo, Japan following the Allied bombing campaign, 1945. (Photo Credit: Universal History Archive / Universal Images Group / Getty Images)

By 1945, Japan found itself in an increasingly untenable position. Years of sustained conflict had severely diminished its military capabilities, with the United States particularly to blame. The country’s strategic island-hopping campaign had effectively isolated Japan, severing its connections to occupied territories in the Pacific. This isolation was compounded by a stringent naval blockade and a relentless aerial bombing campaign that targeted Japanese cities and industrial centers, crippling the nation’s war effort.

The scarcity of vital resources caused by this led to widespread suffering and hardship among the Japanese populace. Food and fuel shortages became acute, with the average civilian’s caloric intake dropping to an unhealthy 1,680 per day. There was also a shortage in working-age males, given the majority of those able to fight had been recruited into the military.

The realization that the war was unwinnable, given the dire state of the nation’s military and resources, became a key factor in leadership’s decision to surrender.

Japan wanted to preserve its Emperor system

Emperor Hirohito on horseback
Japanese Emperor Hirohito, 1940. (Photo Credit: Hulton-Deutsch Collection / CORBIS / Getty Images)

A unique aspect of Japan’s surrender negotiations was the desire to preserve the emperor system; the government insisted on maintaining the position as a non-negotiable term. The fear that unconditional surrender would lead to the dismantling of the monarchy was a significant concern, influencing the decision-making process at the highest levels.

What ultimately came from the discussions was the “Humanity Declaration,” in which Hirohito agreed to a “Symbolic” emperor system, which saw a denial of the emperor’s divinity and, instead, positioned him as “the symbol of the State and of the unity of the people.”

Essentially, the emperor, while still a figurehead, would no longer hold the most political power. Instead, a new constitution would be adopted.

Facilitating Japan’s surrender

Japanese officials standing together on the deck of the USS Missouri (BB-63)
Japanese surrender aboard the USS Missouri (BB-63), 1945. (Photo Credit: Prisma Bildagentur / Universal Images Group / Getty Images)

The process of facilitating Japan’s surrender was marked by significant diplomatic and communicative efforts. Behind the scenes, diplomats and intermediaries worked tirelessly to establish a channel of communication between Japan and the Allied forces. These efforts were aimed at finding a mutually acceptable solution that would allow the country to surrender while addressing the concerns of all parties involved.

With all the aforementioned factors piling on top of the each other, the decision was ultimately made for Japan to surrender, with Emperor Hirohito announcing the news to the public via a radio broadcast on August 15, 1945.

The first time he’d spoken to average citizens directly, the emperor explained, “The war has lasted for nearly four years. Despite the best that has been done by everyone – the gallant fighting of the military and naval forces, the diligence and assiduity of our servants of the state, and the devoted service of our one hundred million people – the war situation has developed not necessarily to Japan’s advantage, while the general trends of the world have turned against her interest.”

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Just over two weeks later, aboard the American battleship USS Missouri (BB-63), the Japanese Instrument of Surrender was signed. Those present included representatives from the Empire of Japan and the Allied nations, with the most notable being Gen. Douglas MacArthur, Fleet Adm. Chester Nimitz and Chief of the Japanese Army General Staff Gen. Yoshijirō Umezu.

June Steele

June Steele is one of the authors writing for WAR HISTORY ONLINE