If you wish to drive an automobile in Japan, here is how.
You need a driver’s license to drive an automobile in Japan, and there are a few ways to obtain a valid driver’s license. One is to switch your foreign driver’s license to a Japanese driver’s license. Another is to attend a driving school here.
1) Switching foreign driver's license to a Japanese driver's license
Here is a comprehensive explanation on how to do it.
Gunma Prefectural Police also posts information on the procedure in detail.
2) Attending a driving schoole
Effective July 2009, Gunma Prefecture gives an English written test. Click the below URL address for details.
Driving an automobile will certainly help you get around better in Gunma where public transportation is not as well developed as in Tokyo. Gunma has many beautiful places that are waiting to be seen by you, and local people are nice and friendly. While you are here, you cannot miss experiencing a variety of local delicacies made from home-grown fresh produce, a taste of Gunma to be remembered when you return to your home country.
(Effective August 2010)