The Americans had already bombed Tokyo into ruins five months prior, killing at least 100,000 people and leaving a million homeless. It was the most violent air raid in history, doing more damage than either of the atomic bombings. The Japanese did not surrender.

The point of Hiroshima was not that the USAF could destroy a city, because they had already done that sixty-seven times over the preceding year, but that they could now do it with a single plane and a single bomb. They specifically selected a city which had never been raided before so it would be clear that all the damage had been done by the new weapon.

The Japanese were used to watching hundreds of American bombers destroy a city overnight. Now they had to fear a raid in which hundreds of bombers destroyed hundreds of cities overnight, and then the war would be over because their society would no longer exist.