Do I need a Japanese driver license to drive in Japan or can I just use my international driver permit?
I think you are ok driving in Japan with your International Driver License.
The law seems a little gray in this area. It seems like the intent of the International Drivers Permit is for short, holiday type driving. So, if you are a resident of Japan, I think you should probably get a Japanese driving license.
We offer a lot of information regarding driver license's in Japan here at this link -
We hope you find it helpful...safe driving and Happy Holidays!
It's probably better you give the Japanese police your International driver license anyway. They won't know what to do with it...lol