August 6, 1945

Hiroshima was a flourishing castle town in the Edo period (1603-1868). After the Meiji Restoration, the Higher School of Education opened, and the city began developing a large concentration of army facilities. Thus, it developed a dual reputation for 'education' and 'the military.' Approximately 350,000 persons were in Hiroshima when the bomb exploded.

The structure now called the A-bomb Dome was designed by Czech architect Jan Letzel. It was completed on April 5, 1915 and opened on August 5 of that year as the Hiroshima Prefectural Commercial Exhibition Hall. Its name was changed to the Hiroshima Prefectural Products Exhibition Hall in 1921, and finally to the Hiroshima Prefectural Industrial Promotion Hall in 1933. In addition to displaying and selling prefectural products, it was also used for art shows and other expositions. As the war intensified, however, it housed a number of government agencies.

The atomic bomb utilizes the energy released by the fission of uranium and plutonium to generate far more destructive power than any conventional explosive. Furthermore, the gamma rays, neutron rays and other radiation released by the explosion cause serious physical damage over aperiod of decades.The bomb dropped on Hiroshima was approximately three meters long and weighed four tons. Because the final bomb was shorter than the initial design, it was dubbed `Little Boy`. The bomb carried about 50 kilograms of uranium 235, but the instantaneous fisshion of less than 1 kilogram released the energy equivalent of 16,000 tons of high-performance explosive.

At 8:15 a.m., August 6, 1945, an atomic bomb was used as a weapon for the first time in human history. With a blinding flash, the bomb detonated approximately 600 meters above the city center. The heat rays and blast burned and crushed nearly all buildings within 2 kilometers of the hypocenter, taking thousands of lives. Those who managed to survive, their burned and bloodied clothes hanging in tatters, clambered over the rubble to flee the city.

In an instant, the city was almost entirely destroyed. Most were never identified except by the belongings they left at their families, their bodies or ashes never returned to their families. Most of the belongings displayed here were found by family members who, worried for their safety, went searching through the burned-out ruins.Each of these items embodies human pain, grief, or anger, and silently admonishes us never again to allow such a tragedy.

Damage by the Heat Rays

At the instant of detonation, the temperature at the center exceeded a million degrees Celsius, generating an enormous fireball. Within 1 sec of detonation, it had extended to its maximum diameter of 280 meters. The powerful heat rays inflicted tremendous damage.

Damage by the Blast
At the moment of the explosion, an extremely high pressure of several hundred thousand atmospheres was created. The surrounding air was thrust violently outwards and produced an intensely strong blast. Buildings were crushed and people were blown through the air. Many people were knocked unconscious and injured when lifted and blown through the air. Others were crushed under collapsing buildings.

Damage by the Radiation

The special characteristic of atomic bombs is nuclear radiation, something which conventional weapons never produce. The radiation inflicts severe injuries on the human body. The radiation affected those within about 1 kilometer of the hypocenter who received life-threatening doses. Many of them died within a few days. The acute effects that appeared immediately after the bombing for a short time thereafter manifested in a wide range of symptoms, including fever, nausea, diarrhea, bleeding, loss of fair, and severe fatigue. Vast numbers died. After these acute effects subsided many survivors continue to suffer with keloids, leukemia, cancers, and other aftereffects.

Black Rain

Soon after the explosion, radioactive smoke, dirt, soot, and other matter blown up from the ground surface formed a black cloud. That dirt and soot mixed with water drops in the air and fell as black rain. The black rain was therefore highly radioactive, causing fish in ponds and rivers to die and float to the surface. Most who drank well water in these areas suffered from diarrhea for three months.

aftereffects

The effects of the atomic bomb appeared to have subsided by the end of 1945, but other disorders appeared later. The disorders that appeared from about the time the acute effects were ending were called aftereffects. Beginning with keloids, survivors suffered a significantly higher incidence of cataracts, leukemia, malignant tumors (cancers), and in-utero effects.

War, the A-bomb, and the People of Hiroshima

Hiroshima, with the atomic explosion, lost its foundations as a city. The survivors and A-bomb orphans were devastated. of course, but soldiers home from the front, other returnees from overseas, and those returning from evacuation sites, who were spared the bombing itself, had lost their houses and workplaces. Yet through the followed the bombing, Japan's surrender. and the occupation, the people never lost hope. They struggled continually to get back on their feet.