Ryokan
Ryokan are the top end of Japanese-style accommodations. Many travelers in Japan fall in love with the traditional luxurious Japanese-style inns with immaculate tatami rooms, delicious food and great service. They are usually priced accordingly. In the smaller towns or regional cities, however, a ryokan is often not much more expensive than a minshuku - so even if you're on a budget trip, be sure to ask about ryokan prices just in case. Note that the price you will be quoted almost always includes dinner and the following morning's breakfast (unless it’s listed as “su-domari” which means accommodation only); the dinner is usually spectacular (and often this is reason enough to splurge on a ryokan - after all, a sumptuous meal of local delicacies is one of the true joys of travel in Japan). The breakfast is usually much less ornate. In onsen (hot springs) areas, ryokan are likely to be your only option.
There are ryokan guides available in bookstores in Japan, and travel services can provide some information as well. Also note that there is an increasing amount of information available on the Internet. Get a Japanese friend to do a search in Japanese for the area you want to stay in and the word "ryokan."
For other reference materials that you may find useful in route planning, see RESOURCES.