Sannozan Onsen Zuisenkyo

Located in the town of Genbi, Ichinoseki City, Iwate Prefecture, this single-inn hot spring sits at the foot of the sacred Mt. Sannozan on the northern flank of Mt. Kurikoma, along the Iwai River. Legend holds that the Buddhist priest Jikaku Daishi Ennin once secluded himself here to train, and the inn stands facing this spiritually significant peak. Formerly known as Yabitsu Onsen Zuisenkaku, it lies about 2 kilometers downstream from the Yabitsu Dam, above the celebrated Genbikei Gorge, and was renamed Sannozan Onsen Zuisenkyo on May 1, 2017. The property draws from three distinct hot spring sources of differing character within its grounds, blending them to supply its baths, making it a notable multi-source hot spring inn.

The water is classified as a calcium-sodium sulfate-chloride spring (hypotonic, neutral to weakly alkaline, high-temperature spring) with a pH of 7.5. The source flows at 64 degrees Celsius and roughly 140 liters per minute from a self-flowing well, and is delivered to the baths completely undiluted as genuine source-fed (kake-nagashi) water. The smooth, faintly viscous water forms a thin film on the skin that leaves it moisturized, while its emulsifying action softens and washes away dead skin cells, a hallmark of sulfate springs, one of Japan's three great beauty-bath water types, earning Zuisenkyo its reputation as a Bijin no Yu, or beauty bath.

The main bath, Zuisen no Yu, is a bright hall with large windows that let in abundant natural light, complemented by a rock-lined outdoor bath, a women-only outdoor bath called Seseragi no Yu, a men's outdoor bath called Shiki no Yu, two private baths named Yoshimi no Yu and Nagomi no Yu, and a sauna. Day-use bathing costs 550 yen for adults (tax included) and is available from 11:00 to 14:50 (last entry 14:00), closed on Wednesdays and Thursdays. The inn offers 43 guest rooms accommodating up to 234 guests, with cuisine featuring Maesawa beef and seafood from the Sanriku coast, alongside its signature ginger mochi, served since the inn's opening.