Sakurada Onsen Sanpoen

Sanpoen is a 10-room hot spring inn nestled in the rural hills of Matsuzaki on the Nishi-Izu (western Izu) coast, in Sakurada, Matsuzaki Town, Kamo District, Shizuoka Prefecture. Standing alone amid rice paddies along the Naga River, about five minutes inland from the coast, the inn traces its origins to 1980, when a former mikan (mandarin orange) farmer struck his own hot spring source and opened for business. Rebuilt into its present 10 rooms in 1995, it is a member of the Japan Association of Secluded Hot Spring Inns and enjoys a quiet following among bathers seeking free-flowing spring water.

The spring is a calcium-sodium sulfate spring with a source temperature of about 73 degrees Celsius and an alkaline pH of around 8.4. Boasting an abundant flow of over 600 liters per minute, it is served as a completely free-flowing (kakenagashi) source with no added water, no heating, no recirculation, and no chlorination. The water is nearly colorless and clear with a faint scent of sulfur, and is said to help with cuts, burns, and chronic skin conditions, cherished as a healing and beautifying bath. A drinking-spring station approved by the public health office sits beside the entrance.

The bathing facilities include gender-separated Japanese cypress indoor baths, a large private open-air bath measuring some 10 meters deep, and a private family bath, while three guest rooms feature their own open-air baths. Day-trip bathing is not offered; the baths are for overnight guests only, with stays including two meals starting from roughly 18,700 yen. The inn is closed on Tuesdays and Wednesdays (subject to change for holidays).