Bombing of Hiroshima and Nagasaki: History, Reasons, Deaths, & Aftermath

The bombing of Hiroshima and Nagasaki were American nuclear attacks on the Japanese towns of Hiroshima and Nagasaki in August 1945. Those bombings are credited with effectively bringing an end to World War II, albeit at a horrific cost to the Japanese population and heralded the beginning of the nuclear age.

In the article below, World History Edu explores the history of the bombing of those two Japanese cities, including the reason why the United States took the decision to unleash a never-before-used weapon.

Little Boy and Fat Man

They were two separate atomic bomb attacks; thus, the bombing of Hiroshima occurred on August 6, 1945, and then the bombing of Nagasaki on August 9, 1945. The Americans dubbed the first atomic bomb “Little Boy” and the second bomb “Fat Man,” reflecting their disparate sizes and levels of force.

“Fat Man” was a plutonium implosion nuclear weapon, while “Little Boy” was a uranium gun-based fission tool. They were products of the codenamed US nuclear weapon initiative, the Manhattan Project, a three-year top-secret project that was the biggest scientific endeavor ever. The project cost the U.S. taxpayer about $2 billion.

US Army General Leslie R. Groves supervised the project. However, the prominent American physicist Julius Robert Oppenheimer was the head of the team developing those weapons. Oppenheimer had a team of renowned physicist and other scientists that worked around the clock to realize dream of the world’s first nuclear weapon. Some of those scientists included Edward Teller, Leo Szilard, Enrico Fermi, and Ernest Orlando Lawrence.

Read More: Timeline of Major Events in World War II

Colonel Paul Warfield Tibbets Jr and Major Charles W. Sweeney carried out the Hiroshima and Nagasaki bombings, together with their respective crews, in silver-plated versions of the “Boeing B-29 Super fortress,” thus the “Enola Gay” and the “Bockscar.”

On August 6, 1945, at 8:15 am (US time), Colonel Paul Tibbets piloted the Enola Gay and then dropped Little Boy on Hiroshima by parachute. It detonated 2,000 feet above the city in a blast equivalent to 12–15,000 tons of trinitrotoluene (TNT). The weapon obliterated about five square miles of Hiroshima.

Then three days later, on August 9, 1945, Major Sweeney proceeded to Nagasaki in the Bockscar and dropped the heavy plutonium implosion weapon, “Fat Man,” which was designed to cause a 22-kiloton blast and was more potent than the bomb detonated at Hiroshima.

The “area of practically total devastation” at Nagasaki, however, was much less, at around 2.6 square miles. This was due to the uneven topography of Nagasaki, hence the bomb’s damage was limited to the valleys over which it detonated. The main area of practically total devastation was around 2.6 square miles, which was lesser than the area destroyed in Hiroshima.

Why did the United States drop those weapons on Japan?

Below are some factors that influenced the United States’ decision to drop nuclear bombs on Japan:

1. The US and the Allies wanted Imperial Japan to surrender during the Pacific War and World War II quickly and unconditionally. Early in the 1940s, tensions between Imperial Japan and the US grew worse, especially after Japanese forces chose to attack Indochina to seize the oil-rich East Indies. The Japanese also employed many war strategies, including their infamous kamikaze strikes to destroy US war vessels. Following various fierce attacking responses from the US and the Allies on Japan, they did not back down and later openly declared their intention to fight to the very bitter end. The Japanese government also disregarded the demand of the Allies to surrender unconditionally on July 26, 1945, through the “Potsdam Declaration.” In the weeks that followed, the US gained consent from the other Allies, which ultimately led to US President Harry Truman’s orders for nuclear weapons to be used against Japan.
2. Some say, the Hiroshima and Nagasaki bombings were in a way revenge assaults on Japan for conducting the Pearl Harbor Attack. Again in the 1940s, the US ran a highly effective fuel (oil) embargo against Japan, distressing the country. In response, Japan’s Imperial Navy Air Force conducted a military strike at the US naval base at Pearl Harbor. Soon after the Japanese bombed Pearl Harbor, the US joined Allied Powers and began planning the most devastating attack on Japan, ultimately resulting in the bombing of Hiroshima and Nagasaki.
3. US authorities believed the atomic bombing would bring a fast end to the war without US casualties. At the time, several top American military leaders advocated extending the conventional bombardment of Japan and then launching a large invasion known as “Operation Downfall.” They further warned President Truman that such an invasion might result in over a million American fatalities; hence, using the atomic bombs was their best option. However, considering the moral objections of his army general and secretary and some of the Manhattan Project’s scientists, Truman decided to deploy the atomic bombs on Japan to reduce casualties and hasten the war’s conclusion.
4. It was a well-calculated war move from the US to conquer Japan, highlighting the benefits of their substantial investment in the Manhattan Project, the development of nuclear weapons, and their superiority over the Soviet Union. In addition, many senior US Army generals believed that the bombs’ lethal force would give the US a powerful status to control the postwar world.

Why Hiroshima and Nagasaki?

The purpose of the bombings was to cripple Japan’s military prowess. Therefore, Hiroshima was the primary military target because it was one of Japan’s most important military centers, serving as the headquarters of the “Chugoku Regional Army” and the Imperial “Second Army.”

Also, Hiroshima served as the principal military shipping port for Japanese troops and supplies and the location of one of the biggest military supply depots. With over 300,000 inhabitants, it was Japan’s seventh-largest city in the 1940s.

The Soviet Union’s war declaration on Japan on August 8, 1945, a few days after the bombing of Hiroshima, could have sparked the bombing of Nagasaki. It’s possible that President Harry Truman ordered dropping the atomic bomb on Nagasaki to compel Japan to surrender and deter the Soviet Union by demonstrating American military superiority.

Deaths & Aftermath

Investigations conducted by Manhattan Project scientist Philip Morrison, and the US Department of War, stated that the bomb at Hiroshima destroyed 26 of the city’s 33 firefighting stations and killed or injured three-quarters of the city’s firefighting workers.

Unfortunately, all but one hospital in the city was partially or entirely damaged. In addition, only 30 of the 298 licensed doctors escaped injuries and were able to provide healthcare services to survivors.

Of the 2,400 nurses and orderlies in the city, more than 1,800 died or suffered life-threatening injuries. Between 90,000 and 147,000 people died due to the atomic bombings in Hiroshima, and between 39,000 and 81,000 died in Nagasaki.

Unfortunately, many people died in the few months after the bombing due to radiation poisoning, burns, and severe injuries worsened by infections and malnutrition.

On August 10, 1945, a day after Nagasaki was bombed, the Japanese government declared its acceptance of the conditions of surrender as stated in the Potsdam Declaration.

The United States then expanded its sphere of influence in Japan through the Occupation of Japan between 1945 and 1952. The US occupation had a long-lasting impact on the country’s government, economy, military, and culture. For instance, Japan’s constitution as of October 2022 was drafted by a staff of US General Douglas MacArthur, and it has been in effect since 1947.

Extensive developmental projects occurred in Hiroshima and Nagasaki during the US occupation. A thorough planning program was implemented in Hiroshima in 1950, and the city swiftly developed into an industrial hub, whereas Nagasaki was mainly utilized for tourism.

The “Peace Memorial Park” in Hiroshima also honored those who perished in the bombing. Furthermore, the Japanese government vowed to provide free healthcare to the surviving victims for the rest of their lives.

Many research organizations conducted surveys and studies investigating the biological and medical consequences of radiation from the bombs.

Specifically, they concentrated on the health impacts of radiation on the offspring of survivors conceived after exposure to the bombs. This was because it was discovered that pregnant women who experienced the bombings had an increased incidence of miscarriage and death.

However, there were relatively low radiation-related disease cases found in the children, even though there was scientific proof that the children of survivors were more likely to have cognitive impairments, growth retardation, and a greater likelihood of developing cancer.

Generally speaking, the resilience of the younger generations of Hiroshima and Nagasaki inspires hope that the cities will eternally continue to recover from the bombing.

As of October 2022, radiation levels at Hiroshima and Nagasaki were comparable to the natural radioactivity levels on Earth. The current radiation in both cities has no adverse or extreme effects on humans, animals, and vegetation.

Were the Bombings of Hiroshima and Nagasaki War Crimes?

The ethical, legal, and military concerns of the bombings have been the focus of scholarly and public discussion for decades. Some scholars argue that the bombs forced Imperial Japan to surrender, averting the fatalities that an invasion of the country would have brought.

Others have expressed the conviction that atomic bombs were inherently evil, that the bombings were crimes against humanity, and that they constituted war crimes and state terrorism.