Nishiyama Onsen Keiunkan

Keiunkan says its spring was opened in 705 by Fujiwara no Mahito, and in 2011 Guinness World Records listed it as the oldest hotel: "a hot-spring hotel, which has been operating since 705 AD." What is old here is the spring and the business, not the building. The inn was renovated throughout in 1997, and it reopened on March 5, 2026 after another refit that added a cave bath, a ganbanyoku hot-stone bed of local Amehata inkstone and a small history room. It sits far up the Hayakawa valley in Hayakawa town, on the west side of Yamanashi below the Southern Alps, a few bus stops short of Narada Onsen, where the town bus ends. The water is the reason to come. Two sources, a natural spring and a well drilled in 2005, give 2,030 liters a minute at 52°C, alkaline at pH 9.36, and the inn says nothing is heated or watered down anywhere in the building, the taps in the rooms included. There are two outdoor baths that swap between men and women at 8:00 and 20:00, two indoor baths on the top floor, and two private outdoor baths that must be booked. You have to stay the night: the inn takes no day bathers. Getting here takes planning. The only road is Prefectural Road 37, which the town says closes once rainfall reaches 70 mm without a break. The inn's shuttle meets one train window at Minobu Station, and the town bus runs four times a day.