<P> Hiroshima was a minor supply and logistics base for the Japanese military, but it also had large stockpiles of military supplies . The city was also a communications center, a key port for shipping and an assembly area for troops . It was a beehive of war industry, manufacturing parts for planes and boats, for bombs, rifles, and handguns; children were shown how to construct and hurl gasoline bombs and the wheelchair - bound and bedridden were assembling booby traps to be planted in the beaches of Kyushu . A new slogan appeared on the walls of Hiroshima: "FORGET SELF! ALL OUT FOR YOUR COUNTRY!" It was also the second largest city in Japan after Kyoto that was still undamaged by air raids, due to the fact that it lacked the aircraft manufacturing industry that was the XXI Bomber Command's priority target . On July 3, the Joint Chiefs of Staff placed it off limits to bombers, along with Kokura, Niigata and Kyoto . </P> <P> The center of the city contained several reinforced concrete buildings and lighter structures . Outside the center, the area was congested by a dense collection of small timber - made workshops set among Japanese houses . A few larger industrial plants lay near the outskirts of the city . The houses were constructed of timber with tile roofs, and many of the industrial buildings were also built around timber frames . The city as a whole was highly susceptible to fire damage . </P> <P> The population of Hiroshima had reached a peak of over 381,000 earlier in the war but prior to the atomic bombing, the population had steadily decreased because of a systematic evacuation ordered by the Japanese government . At the time of the attack, the population was approximately 340,000--350,000 . Residents wondered why Hiroshima had been spared destruction by firebombing . Some speculated that the city was to be saved for U.S. occupation headquarters, others thought perhaps their relatives in Hawaii and California had petitioned the U.S. government to avoid bombing Hiroshima . More realistic city officials had ordered buildings torn down to create long, straight firebreaks, beginning in 1944 . Firebreaks continued to be expanded and extended up to the morning of August 6, 1945 . </P> <P> Hiroshima was the primary target of the first nuclear bombing mission on August 6, with Kokura and Nagasaki as alternative targets . Having been fully briefed under the terms of Operations Order No. 35, the 393d Bombardment Squadron B - 29 Enola Gay, piloted by Tibbets, took off from North Field, Tinian, about six hours' flight time from Japan . The Enola Gay (named after Tibbets' mother) was accompanied by two other B - 29s . The Great Artiste, commanded by Major Charles Sweeney, carried instrumentation, and a then - nameless aircraft later called Necessary Evil, commanded by Captain George Marquardt, served as the photography aircraft . </P>

When did we drop the atomic bomb on hiroshima