Notes

From August 6 to 15, Hiroshima

。。*The atomic bomb not only killed people but also destroyed such facilities as government offices and hospitals which would have played essential roles in the relief and restoration work.

。。On the evening of August 6, the Hiroshima Prefectural Government Office and Prefectural Air-Defense Headquarters were temporarily established at Tamon-in Temple on Hijiyama Hill.On August 7, they were moved to the Higashi (East) Police Station (in former Shimoyanagi-cho). According to official reports, there were 53 first-aid stations in Hiroshima City.

。。*On August 7, Imperial Headquarters issued the following announcement about the bombing of Hiroshima:

。。"1. Yesterday, on August 6, Hiroshima City was attacked by a small number of enemy B-29s, which left it with considerable damage.

。。 2. The enemy apparently used a new type of bomb in the above attack. The details are still under investigation.

。。*On August 7, U.S. President Harry S. Truman made a statement about he atomic bombing, saying, "Sixteen hours ago, an American airplane dropped one bomb on Hiroshima, an important Japanese army base.That bomb had more power than 20,000 tons of TNT.

。。*On August 8, [there was an air raid of Fukuyama. Imperial Headquarters announced, "On August 8, at about 9:30 p.m., sixty B-29s attacked the vicinity of Fukuyama City with incendiary bombs.

。。*On August 9, an atomic bomb was dropped on Nagasaki. Imperial Headquarters announced on the same day, 1. On August 9, at about 11:00 a.m., two large enemy bombers entered Nagasaki and appear to have used a new type of bomb. 2. The details are now under investigation, but there seems to have been relatively little damage.

。。*On August 10, regarding the damages caused by the air raids of Hiroshima and Nagasaki, the Japanese government protested to the United States via the Swiss government that such attacks were against international law, i.e., the Regulations respecting the Laws and Customs of War on Land, attached paper to the Convention respecting the Laws and Customs of War on Land.

。。*On August 11, a "Student Action Corps", composed of students who were left, was organized to clear up the ruins, and they met at Hiroshima University of Literature and Science (now Hiroshima University).

。。*On August 14, Dr. Yoshio Nishina of the Institute of Physical and Chemical Research reported the results of investigations, determining that it had indeed been an atomic bomb. He had reached this conclusion on August 10, by judging the results of the investigations conducted by experts dispatched by the Ministry of War and others. There was, however, no media release of this fact to the public until August 17.

。。*On August 15, Emperor Showa announced the end of war: "...The enemy used atrocious new bombs, incessantly killing and wounding innocent people, and inflicted devastation of an unfathomable extent..." The Emperor's own voice was broadcast on radio at 12:00 noon on this day, and the Japanese people understood that Japan had lost the war.

Theory of Atomic Bomb

。。Material is made of atoms and at the core of an atom is an atomic nucleus. When an atomic nucleus is split by artificial means, a huge amount of energy is generated. This energy is used to make a weapon for mass killing: an atomic bomb.
。。The splitting of an atomic nucleus is called nuclear fission. Nuclear fission is caused when a neutron collides with an atomic nucleus of nuclear fissile material, such as uranium 235 or plutonium 239. When it happens, two to three neutrons are released, instantly generating a huge amount of energy.

。。The released neutrons then collide with other atomic nuclei and again cause fission, in turn releasing neutrons and a huge amount of energy. When such fission is successively repeated in a very short period of time, an enormous amount of energy is generated instantaneously.

Three Atomic Bombs

。。A certain amount of nuclear fissile material (critical mass) is necessary to cause successive nuclear fission known as chain reaction. Uranium 235 was used as fissile material for the Hiroshima bomb dropped on August 6, 1945, while plutonium 239 was used for the experimental bomb in the world's first nuclear test on July 16 of that year, and also for the Nagasaki bomb dropped on August 9.

。。Because of their shapes, the U.S. Forces called the first uranium-235 bomb, dropped on Hiroshima, "Little Boy", and that dropped on Nagasaki, "Fat Man".

。。While the energy released by the Hiroshima bomb was said to be equivalent to 20,000 tons of TNT, evidence of later studies indicates that its actual force was equivalent to approximately 15,000 tons of TNT. Despite the release of such an enormous amount of energy, it is believed that less than one kilogram of the ten to thirty kilograms of uranium 235 in the bomb achieved nuclear fission.

Damage to the Human Body

。。The physical harm caused by the atomic bomb included "burns" from the intense heat rays and fire, "external injuries" caused, for example, by fragments scattered by the blast piercing people's bodies or by being caught under collapsed buildings, and "radiation damage" to skin and internal organs. It was one or more of these factors that killed and injured people. During the first four to five months after the bombing, radiation damage made the hibakusha's burns and external injuries worse, multiplying the severity of their symptoms.(These are referred to as the acute effects of the A-bomb.)

。。After this initial period, hibakusha suffered various late effects of the bombing, which were mainly attributable to radiation.

Damage to Buildings

。。Hiroshima was nothing but burned debris after the bombing. A photograph taken facing south from the city center shows a wide stretch of ruins,dotted here and there with burned-out shells of concrete steel-framed buildings or brick buildings. Beyond these,the photograph shows Hiroshima Bay and some islands. On top of the destruction caused by the atomic bomb, the Makurazaki Typhoon,which came that September,swept away what little remaind of Hiroshima.

。。According to the figures of the A-bomb damage released by Hiroshima Prefectural Police Headquarters on November 30, 1945, there were 55,000 buildings which were totally burned, 2,290 half burned, 6,820 totally destroyed, 3,750 half destroyed: in total, 67,860 buildings were damaged or destroyed.

What People Called the A-Bomb

。。The survivors called the atomic bomb "Pika-don". "Pika" referred to the flash of light, while "Don" was for the deafening sound of the bomb. It was used in such expressions as "My daughter was killed in the Pika." The expression, "Gen-baku (A-bomb)", an abbreviation of Genshi-bakudan (atomic bomb), began to be used in the year after the bomb.

War Damage to Schools

The damage to schools in Hiroshima Prefecture was reported in October of 1945. In Hiroshima City, school buildings were totally destroyed or burned at 21 primary schools, 9 youth schools, 21 middle schools, and at 3 universities and colleges. The number of dead was approximately 2,000 at primary schools, 300 at youth schools, 7,172 at middle schools, and about 400 at universities and colleges, totaling about 10,000. Considering that there are still many people who have not been accounted for, the casualties were extremely heavy.

Under The Mushroom Cloud	JAPANESE