The Story of Hiroshima
Little Boy was ready for delivery by July 31. On August 2, Hiroshima was specified as the primary target, with Kokura and Nagasaki as alternates. The raid was set for August 6.
While plans for the invasion of Japan were going ahead, preparations were also being made for the use of the atomic bomb. Target recommendations were made by the Target Committee. Among its primary concerns was showing off the bomb's power to the maximum effect. By the end of May 1945, the Committee selected, in order of priority, Kyoto, Hiroshima, Kokura and Niigata. The Army Air Forces were ordered not to firebomb these cities.