Thanks for the link. I didn't try Google as I thought I'd only get Japanese hits! Actually from
www.jmra.or.jp there doesn't seem to be any link to this English page!
Now I'm wondering if you can get the knowledge stuff in English. Of course - the other point is I'm not sure how you are supposed to practice the technical stuff (manouvering/seamanship etc) as you're not allowed to drive a boat without a licence - seems like a bit of a catch 22!!
Still the 4th class licence covers you out to 5nm so it might be worth looking at.