OK, you want a car, here is the deal. It's a certificate of signature and is issued by your embassy. These are issued by your local police superintendent. You also need to bring your gaijin card with you when you buy the car. Taxes Taxes - Taxes suck everywhere.
Japan is no exception.
The tax year is from January 1 - December 31. The rate for the local tax is different depending on where you live. Ask at the ward office. Sometime between February 16 and March 15, get all your employment receipts together and march down to your local tax office. Definitely check with your employer for all the details.