Flight Leonardo da Vinci–Fiumicino Airport departs from Rome Leonardo da Vinci–Fiumicino Airport at 14:55 and arrives at Tokyo Haneda Airport at 10:25.
The flighttime is about 12h 30m. The distance travelled ("as the bird flies"): 14143 Km. So the average speed is roughly 1131 Km.
There is an 7 hour time difference between Rome and Tokyo