In order to bring a car into Japan and drive it, the following conditions 1 through 3 must be met.
1 Temporary import (customs clearance)
The procedures necessary to clear customs can be simplified by using Carnet de Passages en Douane (CPD).
JAF has no information on customs procedures other than the use of CPD.
For other information visit http://www.customs.go.jp/english/index.htm(Japan Customs)
2 Driving vehicle on the road
Registered vehicles of contracting states of the Convention at Geneva 1949 can be driven in Japan with their foreign license plates only if they have cleared customs using Carnet de Passages en Douane (CPD).
Vehicles registered in other countries are required to undergo domestic registration in Japan after clearing customs.
For further details visit http://www.mlit.go.jp/en/jidosha/index.html(Motor Vehicle Inspection and Registration Guide) on the Road Transport Bureau page of the Ministry of Land, Infrastructure, Transport and Tourism website.
3 Driving license
See Valid Driving License In Japan for details.