This was a daylight mission involving 30 planes from the 6th Bomb Group:
Switching to precision bombing for one mission, Sixth crews were briefed for a raid on the Tachikawa Army Air Arsenal. Bad weather cause a change of targets and thirty planes carrying 668 five hundred pounders bombed the primary radar target, the city of Hammamatsu, with unobserved results. Five of the airborne Sixth ships were early returns.
[Pirate’s Log, p. 43]
20th AF Mission 178