The sets were rebuilt from surplus former 581/583 series EMU cars at JNR factories in Tsuchisaki (Akita), Kōriyama (Fukushima), Mattō (Ishikawa), and Kokura (Kitakyūshū).
The delay at the rendezvous had resulted in clouds and drifting smoke from fires started by a major firebombing raid by 224 B-29s on nearby Yawata the previous day covering 70% of the area over Kokura, obscuring the aiming point.
In 1664 Sokuhi left for Nagasaki intending to return to China but was convinced to stay by lord of Kokura and found a new temple Fukujū-ji on Mount Kujū (now in Fukuoka).
The weapon was manufactured from 1897 to 1945 at a number of locations, including the Kokura Arsenal, Koishikawa Arsenal (Tokyo) and Nagoya Arsenal, as well as under contract by private manufacturers including Matsushita, Toyoda Automatic Loom and others.
A new underwater tunnel is being constructed in 2005-6 between Tobata and Wakamatsu wards to link the Hibiki container terminal with Kokura.
The city was fire-bombed in World War II in early August 1945, and the resulting smoke obscured the nearby town of Kokura, causing the planes en route to drop the atomic weapon "Fat Man" to head to their secondary target, Nagasaki.