Shinkabakawa Kanko Hotel Beppin no Yu

Shionoe Onsen, located along the upper reaches of the Koto River in Shionoe-cho, Takamatsu City, Kagawa Prefecture, is considered the oldest hot spring resort in the prefecture. According to the Japan Hot Spring Association, it was discovered roughly 1,300 years ago, and the priest Kobo Daishi (Kukai) later encouraged local people to bathe there, leading to the growth of a settlement. Shinkabakawa Kanko Hotel's own official website credits the revered monk Gyoki with discovering the spring here 1,250 years ago, with Kobo Daishi said to have practiced ascetic training at the site afterward. Affectionately nicknamed 'Beppin no Yu' (beautiful-skin bath), it has long served as a retreat for hot spring cure-seekers as Takamatsu's inner parlor.

The water has a pH of 9.12, placing it firmly in the alkaline range, and is colorless and clear. It is known as a 'beauty-skin bath' for its gentle exfoliating quality that leaves skin feeling smooth. The main bath is not advertised as source-fed (kake-nagashi); it is managed under a circulation system, though details on dilution or chlorine treatment are not specified on the official site.

The hotel houses a large indoor bath called 'Shobu no Yu,' an open-air bath overlooking the mountains, and a low-temperature steam sauna. All 74 guest rooms have their own hot-spring-fed indoor baths, allowing guests to soak at any hour. Day-trip bathing is also available from 10:30 to 21:00 (last entry 20:00), priced at 820 yen for adults, 620 yen for seniors (65 and over), 510 yen for children from elementary school age through 12, and 300 yen for infants aged 2 and up.