Kokura was the primary target of the Bockscar mission that ultimately dropped Fat Man on Nagasaki.
Bockscar took off from Tinian on August 9, 1945, carrying Fat Man, the second atomic bomb used in warfare. The mission plan identified Kokura, a major arsenal and industrial center, as the primary target and Nagasaki as the secondary target.
When the aircraft reached Kokura, cloud cover and smoke obscured the aiming point. The bombing order required a visual approach, so the crew could not release the weapon there. After several attempts and worsening fuel concerns, the aircraft turned toward Nagasaki.
A break in the clouds allowed the crew to make the attack over Nagasaki. The bomb detonated at 11:02 a.m. local time. Kokura’s narrow escape later became associated with the expression “Kokura’s luck,” although the mission’s immediate circumstances involved weather, smoke, fuel limitations, and strict attack procedures.