History: Hours Before Atomic Bombing Of Hiroshima, August 6, 1945, United States

• Japanese realization of the bombing
The Tokyo control operator of the Broadcasting Corporation of Japan noticed that the Hiroshima station had gone off the air. He tried to re-establish his program by using another telephone line, but it too had failed. About 20 minutes later the Tokyo railroad telegraph center realized that the main line telegraph had stopped working just north of Hiroshima. From some small railway stops within 16 kilometers (10 mi) of the city came unofficial and confused reports of a terrible explosion in Hiroshima. All these reports were transmitted to the headquarters of the Imperial Japanese Army General Staff.
Military bases repeatedly tried to call the Army Control Station in Hiroshima. The complete silence from that city puzzled the men at headquarters; they knew that no large enemy raid had occurred and that no sizeable store of explosives was in Hiroshima at that time. A young officer of the Japanese General Staff was instructed to fly immediately to Hiroshima, to land, survey the damage, and return to Tokyo with reliable information for the staff. It was generally felt at headquarters that nothing serious had taken place and that the explosion was just a rumor.
The staff officer went to the airport and took off for the southwest. After flying for about three hours, while still nearly 100 miles (160 km) from Hiroshima, he and his pilot saw a great cloud of smoke from the bomb. In the bright afternoon, the remains of Hiroshima were burning. Their plane soon reached the city, around which they circled in disbelief. A great scar on the land still burning and covered by a heavy cloud of smoke was all that was left. They landed south of the city, and the staff officer, after reporting to Tokyo, immediately began to organize relief measures.