The Path from the Atomic Bombing to Reconstruction of Hiroshima

1889: Ujina Port was completed.

The school is known as the leading institution in the field of education in western Japan along with the Tokyo Higher Normal School. Moreover, many national government offices and branch offices of nationwide business were established in the city.
Hiroshima's history as a center of administration, military operations, and educational pursuits led to its transformation into a modern city.

1929: A poison gas production facility on Okunoshima Island was constructed.

The atomic bomb was dropped on Hiroshima.

August 6, 1945–8:15 am:

The Enola Gay, a B-29 bomber, departed from Tinian Island in the Mariana Islands and headed straight to Hiroshima with an atomic bomb “Little Boy.”

On August 6 in the morning, the weather in Hiroshima was sunny, but at 8:15 am., the serenity was shattered when the Enola Gay dropped an atomic bomb. After falling for approximately 43 s, it exploded mid-air in a nuclear eruption nearly 600 m above the Shima Hospital, slightly southeast of the Aioi Bridge, which was the target. Upon explosion, a gigantic fireball appeared, emitting intense heat rays that caused the ground temperatures of the surrounding area to reach from 3,000°C to 4,000°C. Also, the intensive bomb impact created maximum wind speeds of 440 m/s at the hypocenter. The blast spread out rapidly and swept the entire city in about 10 s.

Although the heat rays were only emitted for a short span of time, their extreme intensity caused anyone within a 1-km radius from the hypocenter either to die on the spot or to receive multiple severe burns. Even people over 3 km away from the hypocenter suffered severe burns on the exposed parts of their bodies. Wooden structures located within 2 km of the hypocenter were completely destroyed, and there were people trapped under the remains.

Shortly after, the fires broke out spontaneously from the heat rays, and the initial blazes that started among ruined buildings spread rapidly. Thirty minutes after the explosion, Hiroshima was covered in a disastrous firestorm. Everything within a 2-km radius of the hypocenter was engulfed in flames, and many people were burned to death.

Radioactive waves emitted from the explosion caused severe damage to the human body. At a distance of 1 km from the hypocenter, neutrons and gamma rays gave off four grays of radiation, sufficient to cause the death of one out of every two people. One after another, people with no external injuries became sick after a couple of days and later died. People who were not directly exposed to the atomic bombing were also exposed to radiation. This included those who lived on the outskirts of town, where people were not directly exposed to the bombing but were exposed to the radioactive black rain that fell, and those who were exposed to residual radiation upon entering the city.

On August 6, the day of the atomic bombing, the population of Hiroshima is estimated to be about 350,000 people, including inhabitants, military personnel, and people who lived outside the city and commuted to the city for work. At that time, there were not only Japanese people but also numerous people of different nationalities living in the city. They included Japanese-Americans born in the United States, exchange students from Southeast Asian countries, people from the Korean Peninsula and Taiwan, which had both been under Japanese colonial rules at that time, and people from the Chinese mainland. None of them escaped the devastation of the atomic bombing. While the exact number of dead people from the atomic bombing is unknown, it is estimated that the number of deaths was approximately 140,000±10,000 at the end of 1945.