Kusatsu Onsen Boun
草津温泉 望雲
Area photo — not the ryokan itself · Yubatake at night, Kusatsu Onsen, Gunma · Σ64 / CC BY 4.0
A Kusatsu inn dating to 1598, with strong, free-flowing acidic water from two springs and a new wing of onsen-bath rooms — but uneven service and dinners that recent guests rate below the baths
Boun traces itself to a bathhouse inn founded in 1598, and its history page lists Kobayashi Issa and the sculptor-poet Takamura Kōtarō among its guests; it moved from the edge of the Yubatake to the hill just above it. Today it has about 38 rooms, including a new main wing (opened January 2025) where every room has its own free-flowing onsen bath. The water is the reason to come: two strongly acidic springs — Bandai (pH about 1.6) and Sainokawara (pH about 2.0) — feed six tubs in three bath halls, free-flowing with a little water added to cool them, never recirculated. Japanese guests rate it 4.8 on Jalan across 2,623 reviews, 4.68 on Rakuten (1,360) and 4.65 on Ikyu (211), with the baths scoring highest. Meals are kaiseki served in several rounds, in your room or a private dining room. The complaints are consistent: in 2025–2026 Ikyu and Rakuten guests reported no greeting or help with bags at the car park, a staff member with a mask under the nose, salty or tired dishes and a skimpy sukiyaki, slow drinks, and voices carrying between the semi-open-air baths of the Unshōan rooms. The steep slope up from the Yubatake is hard for anyone with bad legs. A blogger paid ¥26,400–28,600 per person with two meals in August 2024, and an Ikyu guest paid ¥60,000 for two in 2025.
Room Selection Guide
What the guests who stayed here actually recommendRecommended
Main building Japanese-Western room with onsen indoor bath (opened January 2025)
An 8-tatami room plus a sitting area, living room and two semi-double beds, with its own natural free-flowing onsen bath. Ikyu guests in 2025–2026 called it so spacious they couldn't use it all, and quiet because the sliding doors seal well. Note that the bath is a 'view bath' by the window, not open-air, and a guest on the first floor kept the screens shut because other rooms could see in.
Unshōan Japanese room with open-air bath (4 rooms)
A 12.5-tatami room with a 6-tatami sunroom, a wooden terrace and a semi-open-air bath fed by the Sainokawara spring — good if you want strong water without the shared baths. One 2023 blogger booked it because the large-bath floors hurt bare feet. But two Rakuten reviewers in August 2026 heard the next room's guests clearly, since the baths are divided only by a wooden fence open above, and a 2025 guest could see a private house from the bath.
Request To Avoid
Unshōan standard Japanese room or twin, and main building 10-tatami room
The Unshōan rooms' own baths are not onsen (Jalan states this), and the cheaper main-building 10-tatami rooms have only a toilet and washbasin, no bath. Guests found them old but well kept. Children can't stay in the Unshōan twin or on the 10-tatami plans.
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Dining Deep Dive
Breakfast Consensus
4.2/5A Japanese breakfast served in a private room, including udon — Jalan and Rakuten score it about as well as dinner
Times in August 2024 were 7:30, 8:00 or 8:30. A December 2025 guest felt rushed at breakfast, and a March 2026 guest found the breakfast hot pot already burnt out on arrival.
Dinner Insights
3.9/5Kaiseki served in four or five rounds so hot dishes arrive hot, in your room (no chairs) or the private dining room Unrei, at 18:00–19:00. Bloggers describe wagyu shabu-shabu or sukiyaki, Ise lobster sashimi and Jōshū beef steak, generous portions and top-grade Koshihikari rice; steak, tempura and ayu can be added. Recent reviews are mixed: in 2025–2026 Ikyu and Rakuten guests reported sashimi that wasn't fresh, dried-out appetisers, food that was too salty, a sukiyaki of 'two slices of beef and onion', sake taking 30 minutes and lukewarm tempura at New Year. The inn doesn't sell alcohol on site and in-room drinks are pricey, though one 2026 guest was allowed to bring their own to dinner.
Onsen & Wellness Realities
Two Kusatsu springs, not the Yubatake source: Bandai (very hot, about 94–96°C at source, pH about 1.6) and Sainokawara (about 49.5°C, pH about 2.0), both acidic sulfur-aluminium-sulfate-chloride springs. All six tubs are free-flowing; the posted sign says a little water is added to cool them, with no reheating and no recirculation or filtration.
Three bath halls — Bandai-no-yu, Nishi-no-yu and Yusan-no-yu — each with an indoor and an open-air tub, with men and women swapping sides overnight. Baths are open from check-in to check-out except a short early-morning cleaning break (the official pages give 3:00–5:00); saunas were added in 2024 and close at 23:00. There is no private reservable bath. Guests describe Bandai as stinging and Nishi-no-yu as gentler for sensitive skin; the Bandai open-air tub was too hot to get into in August 2024, and washing areas and changing rooms felt cold in 2025–2026. Several guests found the baths almost empty.
No policy found — contact the inn.
Local Warnings & Nuances
- 01
Check-in 14:00, check-out 10:00 (Jalan lists 15:00 — check your plan). Call from the Kusatsu bus terminal for a pickup; there is no pickup from Naganohara-Kusatsuguchi station.
- 02
The Bōun slope up from the Yubatake is steep; guests with bad legs found it hard, and there are stairs to some baths and to the dining room, with no lift to Bandai-no-yu.
- 03
Arrival has drawn repeated complaints: Ikyu guests in April–May 2025 and June–July 2026 said nobody greeted them or helped with luggage at the free car park.
- 04
Other dated gripes: a kerosene heater smell and a broken room heater (2025), a building layout 'like a maze' (2025), and night-time noise from other guests (2023).
- 05
Children are welcome in most rooms (co-sleeping up to age 5), except the Unshōan twin and the main-building 10-tatami plans. No pets; the whole building is non-smoking.
Sources
The real blog posts and stay reports this article draws on
- 草津温泉 望雲 2022年2月 (4travel.jp)
- 草津温泉 望雲 2022年5月 (4travel.jp)
- 草津温泉 望雲 2022年5月 (4travel.jp, ユタカ)
- 望雲 露天風呂付き客室 2023年 (lisa-mns, Ameba)
- 草津温泉 望雲 宿泊記 2024年8月 (magatama random note, PR)
- 草津温泉 望雲 2025年4月 (hiroshiy0626, Ameba)
- 望雲 露天風呂付き客室 2025年 (chiitaaman, Ameba)
- 望雲 露天風呂付き客室 2026年1月 (pekomama-2019, Ameba)
- 望雲 クチコミ 2026年1月 (4travel.jp)
- 草津温泉 望雲 クチコミ (一休.com)
- 望雲 温泉 (公式サイト)
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Photo credits: Naraya — the entrance, Kusatsu Onsen · Abasaa / Public domain / Hiiragiya — the frontage on Anekoji-dori, Kyoto · Mariemon / CC BY 3.0 / Mukaitaki in the snow, Higashiyama Onsen, Aizu-Wakamatsu · Fumihiko Ueno / CC BY 3.0
Kusatsu Onsen Boun
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