Ryokan is a Japanese-style traditional inn. Ryokan are difficult to find in urban areas. Most ryokan offer Japanese breakfast and dinner. Ryokan are expensive compared to regular hotels, but it is really worth what you pay for. You can experience the traditional Japanese culture, and it is really different experience with staying at a Western-style hotel.
The standard guest rooms of a ryokan are invariably floored with tatami. The tatami is a traditional floor mats made from bamboo straw. It is how the traditional Japanese sleep with. Most of the Ryokan also offer a yukata for their guests. Yukata is a traditional clothing. The guests can experience to take a walk witha yukata.
Most of Ryokan offer hot spring baths. If you wish to pay more, some of them offer private hot spring too. In Japan, you need to pay an additional onsen (hot spring) tax of 150 yen per guest per night. Hot spring bath is one of the most popular experience for the Japanese and the foreign visitors.