Hoshi Onsen Chojukan

What Hoshi Onsen Chojukan Is

Hoshi Onsen Chojukan (法師温泉長寿館, Hōshi Onsen Chōjukan) is a single-inn hot spring on the Hoshi River in Nagai, Minakami Town, Gunma Prefecture, founded in 1875, and three of its buildings (the Main Building, the Large Bath known as Hoshi-no-Yu, and the Annex) were entered on the register of Registered Tangible Cultural Properties in 2006.

The inn sits in a narrow valley south of Mikuni Pass, close to the Niigata border. Hoshi Onsen is not a village with several inns; the name covers this one property. According to the inn, the spring was found by the Buddhist master Kōbō Daishi (Kūkai) on his travels, and the name joins two characters, hō and shi, meaning "Dharma teacher." It is a founding legend that cannot be verified, but it is the story the house itself has passed down.

The inn in its present form dates to 1875, when its founder, Okamura Mitsugu, repaired a plain bathing hut used by local villagers, along with the neglected road and buildings, and opened a lodging that fed and housed travelers.

How the Three Buildings Came Together

The buildings of Hoshi Onsen Chojukan were not raised at one time. The Agency for Cultural Affairs database dates the Main Building to the early Meiji era, Hoshi-no-Yu to 1895 and the Annex to 1940. The inn itself describes the Main Building as dating from its founding year of 1875, which sits comfortably inside the database's "early Meiji" range.

Two newer guest wings stand alongside them and are not registered: Kunzansō, built along the river in 1978, and Hōryūden, rebuilt during the Heisei era. Registration picked out the Meiji and early Showa parts of a complex that has kept growing.

All three buildings were registered on August 3, 2006, under consecutive numbers 10-0188, 10-0189 and 10-0190. Each qualified under the same criterion: it contributes to the historic landscape of the country. The inn's own website gives August 24, the date of the official gazette notice, as its registration date.

Layout of the Hoshi Onsen Chojukan Grounds

The Hoshi River divides the property. On the east bank the Main Building runs north to south, with Hoshi-no-Yu attached at its northern end. The Annex stands on the west bank, also aligned north to south. The database descriptions are the source for this arrangement.

Arriving guests see the cedar-bark roof and entrance of the Main Building first. By the door is a red postbox still in daily use, and just inside to the left is an Irori hearth where a wood fire is lit every day. The long river-facing side of the Annex is best seen across the water from the Main Building side.

The poets Yosano Akiko and Yosano Tekkan, the novelist Kawabata Yasunari and the poet Wakayama Bokusui are among the writers known to have stayed. In the Japanese National Railways era, Hoshi-no-Yu appeared on a well-known Full Moon travel poster featuring the actors Uehara Ken and Takamine Mieko. Calligraphy and papers linked to these guests hang inside.

Getting to Hoshi Onsen Chojukan

By rail, start at Jōmō-Kōgen Station on the Joetsu Shinkansen. A route bus runs to Sarugakyō in about 30 minutes; change there to the town bus for Hoshi Onsen, about 20 minutes more. The inn notes that only two town buses run in the morning and two in the afternoon, so check the timetable before setting out. A bus timetable starting at Jōmō-Kōgen Station is posted on the inn's website.

By car, leave the Kan-etsu Expressway at Tsukiyono Interchange, follow Route 17 to Sarugakyō (about 20 minutes), then Prefectural Road 261 for about 12 minutes. Drivers coming from Niigata can use Yuzawa Interchange and Route 17. Snow usually lies about 1 meter deep in winter, and the inn strongly recommends winter tires for visits between December and March.

Visiting and Bathing at Hoshi Onsen Chojukan

Hoshi Onsen Chojukan is a working inn with no architectural tours. There are two ways inside the three buildings: stay the night, or come for day bathing.

Day bathing runs 11:00 a.m. to 2:00 p.m., with reception 11:00 a.m. to 1:30 p.m. The fee is 1,500 yen for adults (junior high school age and up) and 500 yen for children aged 3 through elementary school. It is unavailable on Wednesdays for scheduled cleaning, and there are other irregular closures. A bath-and-lunch option is also offered, with the last meal served at 12:30 p.m. (all confirmed on the inn's website on September 25, 2026).

Day visitors can use the two baths where water rises directly from beneath the floor: Hoshi-no-Yu, which is mixed-gender, and Chōju-no-Yu, reserved for women. At Hoshi-no-Yu, bathing garments and towels wrapped around the body are not permitted.

The inn's website does not set out a photography policy. Before taking pictures in the baths or anywhere other guests may appear, ask the front desk. The main telephone number is 0278-66-0005.