Booking a Japanese ryokan

Sadly, I haven't had the chance to stay in a Japanese ryokan (guesthouse) yet. With luck, I will in the future. In the meantime, I did stumble across an English-language website that handles bookings for ryokan across the country, JapaneseGuestHouses.com. It gets praise for good service in two reviews on Trip Advisor (even if the reviewers were less than complimentary about the actual accommodation).