reinforced concrete Niigata Joint Chiefs of Staff military Kokura XXI Bomber Command Hiroshima Kyoto
Hiroshima was a supply and logistics base for the Japanese military. The city was a communications center, a key port for shipping, and an assembly area for troops. It supported a large war industry, manufacturing parts for planes and boats, for bombs, rifles, and handguns. The center of the city contained several reinforced concrete buildings. Outside the center, the area was congested by a dense collection of small timber 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. It was the second largest city in Japan after Kyoto that was still undamaged by air raids, primarily because it lacked the aircraft manufacturing industry that was the XXI Bomber Command's priority target. On 3 July, the Joint Chiefs of Staff placed it off limits to bombers, along with Kokura, Niigata and Kyoto.
