Kokura was the primary target of the second U.S. atomic-bomb mission on August 9, 1945.
The B-29 Bockscar departed Tinian carrying Fat Man, with Kokura listed as the primary target. When the aircraft reached the city, clouds and smoke prevented the bombardier from obtaining the required visual sighting. The crew then proceeded to the secondary target, Nagasaki, where a brief break in the clouds allowed the bomb to be released.
Kokura was an important industrial and military center, including the Kokura Arsenal. Smoke from earlier bombing around nearby Yahata and local industrial activity contributed to the difficult visibility. The phrase “Kokura’s luck” later became associated with the city’s escape from the atomic attack, although the mission was governed by weather, fuel, and targeting procedures rather than chance alone.
Nagasaki was bombed instead at about 11:02 a.m. Japan announced surrender six days later, after the atomic attacks and the Soviet Union’s entry into the war.