Killing 214K to Save 30M

On August 6, 1945, the United States dropped the atomic bomb "Little Boy" on Hiroshima, Japan, killing approximately 140,000 people by the end of the year, mostly civilians. Three days later, a second bomb, "Fat Man," struck Nagasaki, claiming around 74,000 lives. These bombings remain the only instances of nuclear weapons used in warfare, sparking intense debate over their necessity and morality. While the devastation was undeniable, it was a necessary act that saved untold thousands of American military lives and millions of Japanese civilians, particularly women, who were mobilized to resist an Allied invasion with bamboo spears or face death by suicide rather than capture. The bombings averted a catastrophic invasion, aligning with President Harry S. Truman’s goal to minimize loss of life while securing Japan’s surrender.

By mid-1945, Japan’s military position in World War II was dire. The Allies had decimated Japan’s navy, imposed a naval blockade, and conducted relentless firebombing campaigns, devastating 64 cities, including Tokyo, where a single raid killed approximately 125,000 people. Despite these losses, Japan’s leadership, driven by the bushido code emphasizing honor and sacrifice, refused the Potsdam Declaration’s call for unconditional surrender on July 26, 1945. Japanese military planners prepared for Operation Ketsugō, a desperate defense of the home islands, anticipating Allied invasions codenamed Operation Olympic (Kyūshū, October 1945) and Operation Coronet (Honshū, March 1946).

Operation Ketsugō mobilized not only 2.3 million regular troops but also a civilian militia of approximately 28 million, including women, children, and the elderly, trained to fight with rudimentary weapons like bamboo spears and satchel charges. Japanese documents estimated up to 28 million civilian deaths in a prolonged defense, reflecting the government’s willingness to sacrifice its population to avoid the dishonor of surrender. The bushido mindset, which prized death over capitulation, led to policies encouraging mass suicides, as seen in Okinawa, where civilians were given hand grenades to kill themselves rather than be captured. Women, in particular, were indoctrinated to view surrender as shameful, with many prepared to fight or die to protect national honor.

In 1985, when I was a college student in Tokyo, my landlady told me how, when she was one of many teenage girls working in a factory forty years earlier, a soldier had come in one day, handed them all bamboo spears, and drilled them in how to attack the Americans when they invaded the main islands. Teenage girls, never trained to fight, would have been forced to advance on the invading Americans with bamboo spears and satchel charges.

American planners estimated catastrophic losses for an invasion. The Battle of Okinawa (April–June 1945) resulted in 49,000 American casualties, including 12,000 deaths, against 110,000 Japanese soldiers and over 100,000 Okinawan civilians. Projections for invading Japan’s main islands varied, with estimates of 1.7 to 4 million American casualties, including 400,000 to 800,000 deaths, and Japanese casualties potentially reaching 5 to 10 million. President Truman, informed by these figures, sought to avoid an invasion, stating his objective was to “save as many American lives as possible” while expressing “human feeling for the women and children of Japan.” The atomic bomb, developed under the Manhattan Project, offered a means to force surrender without a ground assault.

The atomic bombing of Hiroshima, while horrific, likely prevented a far greater loss of life. The immediate death toll of approximately 140,000 in Hiroshima (and 74,000 in Nagasaki) pales in comparison to the projected casualties of an invasion. They achieved Japan’s surrender on August 15, 1945, six days after Nagasaki and the Soviet invasion of Manchuria, averting the need for Operation Olympic and Coronet.

For American troops, the bombings were a reprieve. A 21-year-old second lieutenant recalled crying with relief upon hearing the invasion was canceled: “We were going to live. We were going to grow up to adulthood after all.” An American friend of mine, now 75, is sure he never would have been born if the atom bombs hadn’t been dropped, because his father, having survived the Battle of Okinawa, would have had to continue fighting the Japanese until the war ended. My friend’s father, while in the Pacific, would have learned a saying that reflected the soldiers’ grim outlook on the war’s duration: “In the sticks in ’46, almost heaven in ’47, Golden Gate in ’48.” The phrase expressed their belief that the war against Japan would drag on for years, with a return home via San Francisco’s Golden Gate not expected until 1948, by which time the soldiers then in Okinawa knew they would likely be dead.

The Japanese military’s execution of American prisoners in the event of an invasion, as revealed by intelligence intercepts, further justified Truman’s decision to avoid a ground assault. The atomic bomb, by shocking Japan’s leadership into surrender, halted this cycle of sacrifice. Emperor Hirohito’s August 15 rescript cited the bomb’s “incalculable” power as a reason for capitulation, alongside the Soviet invasion, indicating its decisive impact.

Scholarly support for this argument includes historian Antony Beevor, who notes that the bombings were seen as moral at the time to achieve a rapid victory and save American lives, though he acknowledges the ethical cost of civilian deaths. Tom Lewis, in Atomic Salvation, argues the bombings saved up to 32 million lives by averting a prolonged war, including Soviet occupation of northern Japan, which could have led to further civilian suffering. The bombings also demonstrated the horrors of nuclear warfare, establishing a taboo that has prevented their use since, potentially saving millions in future conflicts.

Critics argue that the bombings were unnecessary, as Japan was already on the brink of surrender due to the naval blockade, firebombing, and the Soviet invasion of Manchuria on August 8, 1945. Historian Gar Alperovitz contends that modifying the demand for unconditional surrender to allow Emperor Hirohito to remain could have ended the war without nuclear weapons. The United States Strategic Bombing Survey concluded Japan would have surrendered by late 1945 without the bombs or an invasion. These arguments suggest alternative paths could have spared Hiroshima’s civilians.

Ethically, the deliberate targeting of civilians raises profound questions. The Target Committee prioritized the bomb’s psychological impact on Japan’s population, choosing city centers over military targets. Critics like Roy Ceustermans argue that Japan’s military defeat was imminent, rendering the bombings unjustifiable. The moral cost is further underscored by the long-term effects on hibakusha, including leukemia, cancer, and discrimination, as noted by Nihon Hidankyo, the 2024 Nobel Peace Prize recipient.

However, these counterarguments overlook Japan’s resolve to fight on. The government’s rejection of the Potsdam Declaration and its mobilization of civilians, including women with bamboo spears, indicate surrender was not imminent without a decisive shock. The Soviet invasion, while significant, did not prompt immediate capitulation; Hirohito’s rescript emphasized the atomic bomb’s role. The ethical cost, while grave, must be weighed against the projected millions of deaths in an invasion, including women compelled to fight or die. Truman’s decision, described as the “least abhorrent choice” by Henry Stimson, prioritized ending the war swiftly to minimize overall loss of life. The two atomic bombings killed 214,000 people, yet likely saved millions of lives by averting an invasion of Japan, if not a blockade to starve the Japanese to death.

On August 8, two days after the U.S. dropped the atomic bomb on Hiroshima and coinciding with the bombing of Nagasaki, the Soviet Union launched the Manchurian Strategic Offensive Operation. The invasion primarily targeted Manchukuo, a Japanese puppet state in Manchuria, but also included parts of Japanese-controlled territories in northern Korea, southern Sakhalin, and the Kuril Islands. Had the war continued another few weeks, the Soviet Union might have occupied Hokkaido, if not more of Japan, rather than just the four Kuril islands and the southern half of Sakhalin that it had lost to Japan in the Russo-Japanese War of 1904-05.  

Japan’s leadership had been deeply divided, with significant resistance to unconditional surrender due to the military’s adherence to the Bushido code and fears over the fate of Emperor Hirohito. The Potsdam Declaration, issued by the Allies on July 26, 1945, demanded Japan’s unconditional surrender, threatening “prompt and utter destruction” if refused. Japan’s initial response, conveyed through Prime Minister Kantarō Suzuki on July 28, used the term “mokusatsu,” implying the declaration was ignored or dismissed, though some historians argue it meant Japan was withholding comment pending further discussion.The first clear move toward surrender came after both atomic bombings and the Soviet invasion of Manchuria on August 8, 1945. On August 10, Japan sent a message to the Allies via neutral Switzerland and Sweden, offering to surrender with the condition that the Emperor’s status be preserved. This was not fully unconditional, as it included this caveat. After intense internal debate, and following U.S. assurances that the Emperor could remain as a symbolic figure (clarified in the Allied response on August 12), Emperor Hirohito announced Japan’s acceptance of the Potsdam terms on August 15, 1945, in a radio broadcast, effectively marking the unconditional surrender. The formal surrender document was signed on September 2, 1945, aboard the USS Missouri.