The first bombs dropped at 21:25, with an attack hour over Würzburg set for 21:35 (H). The formation passed over the entire city for the target marker H + 7 minutes (21:42). For this the attack had been preceded at H-9 min. (21:26) with the 627th squadron of Mosquito twin-engined bombers marked with green flares. These illuminated the target area, marking them out by flares on Green parachutes, which the German population called "Christmas Trees." As a marker for the bombers, the sports field on Mergentheimer Strasse was used as a measuring guide. This point was identified at 21:28 with red target marker flares. The bombing was then accomplished with a time lag in sectors ("sector bombing"). The bombers had to fly over the red marker, take a specially assigned altitude and flight path, and trigger their bombs and different times. the target area was marked out like a fan, and the bombers flew in with different release times to ensure a carpet-like coverage. Monitoring the situation was a "master bomber" (at a cruising speed of 350 km/h, each bomber would fly over the entire target area in less than a minute).