I just checked out the guide, "Driving Under Japanese Traffic Law." The good news is that most of it is in English. The bad news is the size of the lettering is about 4pt. Hopefully, I will be able to take the test in about a week. I need to go to a different base to take the test, 30 written and 30 sign multiple choice.
The guide reads like a kids' safety pamphlet, but the signs are at least in color. The wording they use is a little odd. It seems like they try to translate with as many words as possible.
Most of the penalties are levied as jail time. So when the Corps said we are professional drivers they must have meant it.