Before leaving to Japan also make sure if the driving license issued in your country works in Japan! Basically there are two international conventions that regulate issuing the international driving license. The one that you need to have is the international

driving license issued basing on Geneva Convention from 1949. Oh, and one more thing – prepare to drive in left-hand-drive traffic conditions! Personalny that was my first experience of this kind, but I got used to it very quickly and it did not cause any problems.