Japan has some funny tax laws as I understand.
A new car carries very little taxation and the taxes
on that car increase as time passes, making it
cheaper to trade the car in at about 5 years.
They lose 40% of their value after 1 year.
This coupled with the fact that it is expensive to
drive in Japan (toll roads everywhere) tends to keep
the milage down on vehicles.
This is how it was explained to me by the Japanese
guy at Pacific Motors.
This is just good for general info because it all comes
down to trusting the people you deal with, and the only
way to really know the mileage is to get the clip.