Originally Posted by
davetravels
Normally they seem to be at or very close to the calculator, but if you get 636 I'd contest that mileage, I don't see how all three of the normally accurate sources plus your normally accurate source can all be wrong and NW's correct.
EDIT: Even ST downloadable schedule lists 782:
From Seoul Incheon KR ( ICN )
To Tokyo Narita JP ( NRT )
Depart ***
Departure Time 1105
Arrive ***
Arrival Time 1325
Distance 782 mi 1251 km
Duration 2h20m