Flight Narita International Airport departs from Tokyo Narita International Airport at 10:00 and arrives at Dhaka Shahjalal International Airport at 15:10.
The flighttime is about 8h 10m. The distance travelled ("as the bird flies"): 5559 Km. So the average speed is roughly 681 Km.
There is an 3 hour time difference between Tokyo and Dhaka
