At 8:15 a.m., on August 6, 1945, the city of Hiroshima fell victim to the world's first atomic bombing. The entire city was virtually leveled; thousands upon thousands of lives were lost. Many of those who managed to survive suffered irreparable physical and psychological damage and still suffer the effects today.
Hiroshima's deepest wish is the elimination of all nuclear weapons and the realization of a genuinely peaceful international community.
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 a period 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 fission of less than 1 kilogram released the energy equivalent of 16,000 tons of high-performance explosive.
At 8:15 a.m., on 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; thousands of precious lives were lost. Junior high school girls and boys were mobilized to help demolish buildings for fire lanes. Most were never identified except by the belongings they left at their worksites, their bodies or ashes never returned to their families. Most of belongings displayed here were found by family members who, worried for their safety, went searching through the burner-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 millibars (hectopascals) was created. The surrounding air was thrust violently outwards and produced an intensely strong blast. Even at a radius of 500 meters from the hypocenter, this represented a huge force of 19 tons per square meter. It resulted in practically all standing structures being crushed and destroyed.
The blast also picked up human victims and blew them through the air for distances of several meters. The blast lifted and hurled some people several meters. Many received serious injuries or lost consciousness, rendering them unable to escape. Others were crushed or pinned beneath falling buildings. The blast also shattered glass, blowing countless shards deep into victims' bodies. Fragments are still occasionally discovered and removed from survivors seeking treatment for unusual bodily pains.
Damage by the Radiation
Unlike conventional bombs, the atomic bomb emitted massive amounts of radiation that inflicted grave damage. Penetrating deeply into bodies, radiation damaged cells, altered blood, diminished the blood generation function of bone marrow, and damaged the lungs, liver, and other organs.
The explosion left residual radiation on the ground for a long period of time. Consequently, many who entered the city after the explosion to search for family or co-workers, as well as those who entered to participate in relief activities, developed symptoms similar to those resulting from direct exposure. Many died.
Soon after the explosion, radioactive smoke,dirt, soot, and other matter blown up from the ground surface formed a black cloud. Thar 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.
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.
The atomic bombing plunged the people of Hiroshima to the depths of physical deprivation and psychological despair. Those who had survived the bombing were joined by soldiers and civilians site to find their homes and workplaces destroyed.
During the period of confusion following the bombing, as all of Japan struggled through the tumultuous transition from surrender to life under occupation, the people of Hiroshima began to rebuild their lives, hampered by scarcities of flood, money and materials.
contributor — Kazuo Nikawa, Sadao Oshita, Masae Himuro, Shigeko Orimen, Nobuo Tetsutani, Junnosuke Taniguchi, Sumitomo Bank Hiroshima Branch, Sumio Watanabe, Hiroshi Doi, Chiyoko Kosaka, Hiroshima Prefectural Government, Hiroko Yamashita, Akijiro Yashima, Tokuso Wakamoto, Shigeo Sasaki, Masahiro Sasaki, Taiji Obara, Shigemi Hamamoto, US Army
creater — Shigeo Hayashi, Gonichi Kimura