International Driver's License
An international driving permit (IDP) etc. will be required to operate a vehicle in Japan legally.
The nationality (country of origin of passport) will not have any influence on the validity of the license or permit required to drive in Japan.
Japan is extremely rigid when it comes to the implementation of the laws governing the issuance of international driver permits, thus the fact that a particular driver permit was granted in one country to drive does not in any way mean that you will be permitted to drive in Japan.
There have also been confirmations on certain permits; Japan was in the list of countries that can drive when it is not supposed to. It has also been confirmed that agents who issue international driver permits are the ones that misled people that it was acceptable to drive in Japan.