BTW , Kumamoto was on the short list of cities considered for an A bomb attack . Nagasaki was not if I remember correctly . The Kyushu target was Kokura near Fukuoka but because of cloudy skies they flew further west to Nagasaki where skies were clear .
Fortunately for many Allied POWs. After the Yawata iron and steel conurbation had been bombed many prisoners being used as slave laborers in the mines, mills and smelters of this region were gathered at Kokora to be used in similar activities. The smoke from the Yawata raids obscured Kokura pretty completely, so the alternate target of Nagasaki was bombed.