Kouchi Onsen Kanaya Ryokan

Kanaya Ryokan is the sole inn of Kouchi Onsen, set at the foot of Mount Kanaya in the Kouchi district of Shimoda City, Shizuoka Prefecture. Founded in 1867, the final year of the Keio era, it stands only a few minutes on foot from Rendaiji Station on the Izukyu Line, yet is surrounded by quiet wooded hills. The inn has drawn on the spring water welling up at the base of Mount Kanaya since its founding and still owns two private sources, making it one of the most historic bathing inns in the Izu Peninsula.

The water is classified as a simple thermal spring, hypotonic, weakly alkaline, and mild. According to the analysis certificates posted inside the building, one blend of the Kouchi No. 5 and Shimoyuhara sources emerges at 49.8 degrees Celsius with a pH of 7.7, while a blend of the Kouchi No. 5 and Kanaya sources emerges at 36.2 degrees Celsius with a pH of 7.6. The water is colorless, clear, and notably soft on the skin. Nothing is added or altered: no heating, no dilution, no recirculation, and no chlorination, so every tub receives fresh source water around the clock.

The centerpiece is Senninburo, a great bath built entirely of hinoki cypress. Measuring roughly 20 meters long and 5 meters wide, reaching about one meter at its deepest point, it is among the largest all-wooden bathhouses in Japan and is mixed-gender. Women may bathe wearing a bathing garment or towel and have their own separate entrance. The inn also offers Manyo no Yu, a women-only bath built of hiba cypress, a private bath called Issenyu dating from the late Meiji period, and separate open-air baths for men and women with a cascading water jet and a bubble bath. Day-use bathing runs from 9:00 to 22:00, with last reception at 21:00, at 1,000 yen for adults.