> 20% is correct, but only for their first 12 months. Australian
> citizens can stay in Japan for up to 18 months using a working holiday
> visa (tokuteikatsudou), so for the owner of the restaurant it depends
> on when her employee entered Japan. For other nationalities the
> maximum period of stay is only 12 months, so if the employee has been
> in Japan for longer than 1 year it would probably be worth contacting
> the local tax office, not the Nakano office.
>

Thanks clarifying this...
Let me add what somebody else said on this subject:

The rates are listed in ????. Request the specific category
from the tax office.