Eighty-one years ago, the United States dropped the atomic bomb on Hiroshima on August 6, 1945, and on Nagasaki on August 9, 1945. Japan is remembering those days that killed more than 300,000 people and ushered the world in the age of nuclear weapons.
Two of the most consequential events in modern history, the bombing of Hiroshima and Nagasaki, marked their 81st anniversary this week.
Marking the anniversary of the bombing of Hiroshima, on Thursday, Japanese Prime Minister Sanae Takaichi attended the Hiroshima Peace Memorial Ceremony for the Atomic Bomb Victims, offering condolences to the victims and pledging a nuclear-free world.
Today, Hiroshima and Nagasaki stand as symbols of peace and the devastating consequences of nuclear warfare. Here is what you need to know about what happened in Hiroshima and Nagasaki 81 years ago:
1. Why did the US choose Hiroshima and Nagasaki?
The United States did not randomly choose Hiroshima and Nagasaki as the sites of bombardment.
On July 25, they narrowed down the potential targets of the bombing to four cities, namely Hiroshima, Kokura, Niigata, and Nagasaki. Kyoto, too, was initially included but removed for political reasons. Consequently, Hiroshima was bombed on August 6 and Nagasaki on August 9.
Hiroshima’s size and layout made it a suitable test site for the bomb’s destructive power. Its position as a major military centre was also a factor that they considered. The city was home to about 43,000 Japanese soldiers and served as the headquarters of the Japanese Second Army, established to command troops in western Japan.
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Nagasaki was not the primary target. The bomb was initially supposed to be dropped on Kokura, but was shifted due to poor visibility from above there. Since Nagasaki had not been severely damaged by air raids, the impact of the atomic bomb could be assessed. Furthermore, the city was home to many shipyards and steelworks and was a major production centre of military equipment and battleships.
2. The dropping of the bomb
The morning of August 6 was sunny in Hiroshima. The serenity lasted until 8:15 AM, when US B-29 Bomber ‘Enola Gay’ dropped the atomic bomb. After falling for approximately 43 seconds, the 9,700-pound bomb, codenamed ‘Little Boy’, detonated in a mid-air nuclear eruption around 600 metres above the Shima Hospital, slightly southeast of the target, Aioi Bridge.
Upon the explosion of the bomb, a large fireball appeared, emitting intense heat rays, causing the temperatures of the surrounding area to reach as high as 3,000°C to 4,000°C. Maximum wind speeds reached 400 metres/second at the hypocentre, and the blast wave swept the entire city in 10 seconds. Shortly after, fires broke out from the heat rays, leading Hiroshima to be covered in a firestorm 30 minutes after the explosion.
The city of Nagasaki recorded cloudy weather conditions when the bomb was dropped from the B-29 bomber ‘Bockscar’ at 11:02 AM on August 9. The target was a point between Nigiwai Bridge and Tokiwa Bridge on the Nakajima River. However, the cloudy conditions made the target difficult to spot.
The bomb, codenamed ‘Fat Man’, exploded approximately 500m above the ground over the tennis courts at 171 Matsuyama-machi. A large fireball, approximately 280 metres in diameter, was created. Temperatures at the hypocentre reached 3,000°C to 4,000°C, with maximum wind speed at the hypocentre reaching 440 metres/second.
3. The impact of the bomb
In Hiroshima, intense heat rays caused anyone within a kilometre radius to die on the spot or suffer severe burns. Even people over three kilometres away suffered burns. The blast hurled people through the air, trapping them under collapsed buildings or crushing them to death.
Wooden structures within two kilometres were destroyed. When the firestorm broke out, everything within two kilometres was engulfed in flames. At a distance of 1 km from the hypocentre, radiation gave off four greys, enough to kill one out of every two people. Those not directly exposed were also affected.
In Nagasaki, 73,884 were killed and 74,909 injured, with almost 36% of the houses damaged. The fireball reached 280 metres in diameter. Near the hypocenter, all burnable things ignited. The blast crushed many under collapsed buildings, and glass shards showered survivors.
Many who appeared uninjured died from radiation exposure, and radioactive fallout and ‘black rain’ caused further harm. The Nagasaki Medical College, 500 metres from the hypocenter, was seriously damaged, and survivors could not receive sufficient treatment due to the overwhelming number of injured and lack of medical supplies.
Hiroshima’s population was estimated at 350,000 and Nagasaki’s at 240,000, including people from Korea, Taiwan, and Southeast Asia, the regions under Japanese colonial rule at the time. Approximately 140,000 had died in Hiroshima by the end of 1945.
4. The survivors of the bomb
Survivors of the atomic bombing are known as ‘hibakusha’. They suffered long-term effects from radiation exposure, including cancers, leukaemia, and other illnesses. The effects of radiation are still felt to this day and have killed tens of thousands decades after 1945. The total death toll from the bombing exceeds 300,000, including those who died from long-term radiation effects.
The hibakusha faced social stigma in post-war Japan. Many survivors were told ‘don’t get married’ or ‘don’t approach people, you might infect them’. The Japanese government has recognised the hibakusha and provides medical support, but the trauma and discrimination continued to affect them.
As of today, around 91,000 victims are still alive with an average age of 86 years. The high ages of hibakusha have increased the urgency for documenting their narratives.
5. The aftermath
Days after the bombing of Hiroshima and Nagasaki, on August 15, Emperor Hirohito announced Japan’s surrender. The formal surrender was signed on September 2, 1945, aboard the USS Missouri.
After the war, Hiroshima was rebuilt as a ‘Peace Memorial City’ and Nagasaki as an ‘International Culture City’ under special laws enacted in 1949.
The closest surviving building to the Hiroshima hypocenter was preserved as the Atomic Bomb Dome, now a UNESCO World Heritage site.
In Nagasaki, the hypocenter was transformed into the Peace Park, with construction completed in 1955. Both cities opened memorial museums in 1955 to exhibit atomic bomb-related materials and convey the horror of nuclear weapons.
Today, Hiroshima is a city of 1.2 million people, and Nagasaki of nearly 600,000. Both cities hold their annual peace ceremony on the days that they were bombed, with both events attended by representatives from around the world.