Flight Leonardo da Vinci–Fiumicino Airport departs from Rome Leonardo da Vinci–Fiumicino Airport at 12:30 and arrives at Tokyo Narita International Airport at 10:30.The flight has a short stop at Moscow.
The flighttime is about 15h 00m. The distance travelled ("as the bird flies"): 14214 Km. So the average speed is roughly 948 Km.
There is an 7 hour time difference between Rome and Tokyo