Day-use bathing and the lunch-break plan can also close on irregularly announced dates beyond the regular cleaning day; check the official site's notices before a visit.
Adults (junior-high age and up) are ¥1,500, children (age 3 through elementary school) ¥500, for bathing only. Lunch-set plans that add a meal to the bath run ¥4,000 to ¥6,000 and already include bath admission, with lunch orders taken until 12:30. A bath towel can be rented and a face towel bought on-site. A few announced dates carry different event pricing, around ¥2,000 to ¥2,500.
Uses natural hot spring water
Open-air outdoor bath
The outdoor bath (Tamaki-no-yu) is used on a rotating men's/women's schedule, per Google reviews.
Enclosed indoor bathing area
Confirmed by a hot-spring association listing: 3 indoor baths total, with the rotenburo used on a rotating basis.
Private onsen bath in guest rooms, for overnight guests only
Shared bathing area for all genders
Mixed bathing isn't available during women-only hours.
Welcomes children and families
Day-use bathing has a published child rate (age 3 to elementary school); no age restriction stated. Note the main bath is mixed bathing.
Restaurant or dining open to visitors (not just hotel meal plans)
Lunch/dining sets are open to day-trip (non-lodging) visitors as part of the day-use bathing offering, reservation required for some.
Shower, wash stations, soap and shampoo provided
Body soap/shampoo confirmed for the Choju-no-yu bath. The historic mixed bath Hoshi-no-yu famously has none: a Google review states 'カランも椅子も石鹸やシャンプーもありません' (no taps, stools, soap or shampoo) - bathers scoop water from the tub itself.
Towels available to rent or borrow
Bath towel is rented; face towel is sold, not rented.
On-site or nearby parking available
Mountains
River
ForestThe Hosokan bath at Hoshi Onsen Chojukan is a high-ceilinged Meiji-era wooden hall that looks much as it did when it was built in the 1880s. Its most unusual quality is that the spring water rises visibly through the pebble floor of the bath, so you can watch it bubble up from below. The bath is mixed (konyoku), and the atmosphere tends to be peaceful; nobody seems to pay much attention to anyone else. The inn has been here for about 150 years, set in forest beside a small mountain river, and the sense of time standing still is genuine. There is also a women's indoor bath and a rotenburo for other times.
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Reserve or check availability on a booking site.
📍Hoshi Onsen Chōjukan, Gunma (pt.3) A little more about the food. Dinner and breakfast are served in a separate shared room, and it was quite noisy in places. Dinner itself was fairly modest, the first 5 photos are from the first day and the last 3 are from the second. Since we stayed for 2 nights, they offered us a kind of lunch during the day, for an extra charge: soba or udon 20.12.2025, 21.12.2025
📍Hoshi Onsen Chōjukan, Gunma (pt.2) There are only three types of baths at this onsen: Hoshi no Yu: the main highlight of this onsen, a separate bath pavilion. Its special feature is that the water in the tubs rises from the bottom, through pebbles. There are no showers at all here, you undress and go straight to the bath. Closer to the entrance the water is hotter, in the farther tubs it is cooler. This is a mixed onsen, and for most of the time it is open to everyone, but there are two hours a day when it is open only to women, and that is when I went. Tamaki no Yu: there is an indoor bath and a large stone rotenburo. In the rotenburo the water is cooler. Choju no Yu: a wooden indoor bath, although here too the water in the bath rises from the bottom, not from a tap. I did not go here, but my onsen companion liked it too. 20.12.2025, 21.12.2025
📍Hoshi Onsen Chōjukan, Gunma (pt.1) A secluded ryokan in the middle of the forest, made up of four buildings. We stayed in the newest one and booked a Japanese-style room. The room itself is divided into 2 parts, a tatami room where futons are laid out at night, and a second room, or rather a kitchen with a small stove, sink, refrigerator, and, most importantly, a kotatsu (if I’m not mistaken, it was a hori-gotatsu with a recessed space for the legs underneath). Since this is a historic ryokan, I was worried we’d be freezing, but no, it was warm and comfortable everywhere, in the room, in the corridors, and really everywhere. In the main building near the entrance there is an irori hearth, and it seems tea is brewed there at certain hours, but we asked exactly when they do it and they made some for us right away, although they seemed very unhappy about it! 🫠 There was still very little snow in December, but there was plenty of mud around, so at the ryokan exit they offer rubber boots so you can walk around comfortably. The main downside for me is that, despite it being December, there were BUGS in the ryokan. They got into the room, and it wasn’t clear from where, since we didn’t open the windows and there didn’t seem to be any gaps anywhere. They were outside the room too, lying around on the stairs and in the passages between the buildings(( Another downside, probably, is that it’s not very convenient to get here by public transport, because the ryokan is literally in the forest, and there’s nothing around it. You can only go for walks in the forest, and there are signs there saying “beware of bears”. But if you want to chill in an onsen and sit in total silence in the middle of nowhere, this is a good option! 20.12.2025, 21.12.2025
