Kokura was the primary target of the 9 August 1945 atomic-bomb mission that ultimately struck Nagasaki.
The B-29 Bockscar carried the Fat Man bomb from Tinian toward Kokura, an industrial city containing major military facilities. When the crew arrived, cloud cover and smoke obscured the aiming point. The mission orders required a visual bombing run, so the crew made repeated attempts to locate the target.
With fuel running low, the aircraft diverted to its secondary target, Nagasaki. A break in the clouds eventually allowed bombardier Kermit Beahan to make the required visual approach, and Fat Man was dropped at about 11:02 a.m. local time.
The episode helped create the expression “Kokura’s luck,” describing how weather and smoke shielded the city. Kokura was not spared from wartime danger generally, but it was not hit by the atomic bomb that day.