Nishiyama Onsen Motoyu Horaikan

Horaikan is a single remote inn at Yushima in Hayakawa Town, Minamikoma District, Yamanashi Prefecture, set at the far upper end of the Hayakawa gorge in the foothills of the Southern Japanese Alps. Nishiyama Onsen is said to have been opened around 705 AD in the Asuka period, giving the springs more than 1,300 years of recorded history. Horaikan draws on that same source, and the room where the British missionary Walter Weston stayed while introducing the Japanese Alps to the world still survives inside the building. Self-catering rooms for long therapeutic stays preserve the atmosphere of an old toji bathing village.

The water is a calcium-sodium sulfate-chloride spring, classified as hypotonic and alkaline. The source emerges naturally without pumping at 34 to 38 degrees Celsius depending on the season, with a pH of 9.1 and a yield of 18.7 litres per minute. It is colourless and virtually odourless, but is prized among hot spring enthusiasts for the unusually large golden to orange mineral flakes that occasionally drift through the water.

Bathing is limited to two indoor tubs behind a full wall of glass facing the gorge, with no open-air bath. One tub is gently warmed while the other is left at source temperature for long, slow soaking. The baths are mixed gender, though changing rooms are separated and day visitors are sometimes given separated or private slots. Day bathing runs from 10:00 to 15:00 at 1,000 yen per adult, and because closures are irregular a phone call ahead is advisable.