Flight Haneda Airport departs from Tokyo Haneda Airport at 09:20 and arrives at Taipei Taipei Songshan Airport at 12:30.
The flighttime is about 12h 10m. The distance travelled ("as the bird flies"): 2157 Km. So the average speed is roughly 177 Km.
There is an 9 hour time difference between Tokyo and Taipei
The best day to arrive at Tokyo is Saturday and it would be best to avoid Thursday, as prices are on average 978.54% higher than on Saturday. (Average prices, based on 11640630 datapoints.)
We have a lot more statistics for flights NH 851 and between Tokyo and Taipei.