Deep in the mountains between Kamikochi and Norikura, in the Northern Japan Alps, sits one of Nagano’s best-known hot spring villages: Shirahone Onsen, famous nationwide for its milky-white, mineral-rich water. Among its handful of ryokan, Katsuranoyu Marunaga Ryokan stands out for drawing on two separate spring sources — one feeding a gently warm mixed-gender outdoor bath, the other feeding a private bath so encrusted with mineral deposits that the tub and floor have essentially fused into one.
Why Katsuranoyu Marunaga Ryokan stands out:
- Two distinct spring sources — Shin-Awa-no-yu and Konashi-no-yu — both milky-white sulfur springs
- A mixed-gender outdoor bath kept deliberately lukewarm, ideal for a long, unhurried soak — especially magical under falling snow
- A rarely advertised private bath where decades of mineral buildup have fused the tub to the floor in striking natural sculpture
- A relaxed, low-key atmosphere in one of Nagano’s most scenic mountain settings
- Katsuranoyu Marunaga Ryokan, Shirahone Onsen
Katsuranoyu Marunaga Ryokan, Shirahone Onsen
| Address | 4185-2 Azumi-Shirahone Onsen, Matsumoto-shi, Nagano 390-1515, Japan |
|---|---|
| Phone | +81-263-93-2119 |
| Official Website | maruei.in |
| Day-use Bathing | ¥800 · 11:00–15:00 · Closed irregularly |
| Check-in / Check-out | From 15:00 (last check-in 17:00) / By 10:00 |
| Overnight Rate | From approx. ¥15,900 per person (2 meals included, varies by season/plan) |
| Credit Cards | Accepted (VISA / JCB / American Express / Diners Club / Discover, etc.) |
| Mixed-Gender Bathing | Bathing wrap or rental towel permitted; women can also enter via a separate women-only access point |
Getting There from Tokyo — Access Guide
Shirahone Onsen sits in a remote valley of the Northern Alps, roughly midway between the mountain resort of Kamikochi and the ski slopes of Norikura Kogen. It’s a scenic but genuinely mountainous drive or bus ride, so allow extra time in winter.
🚄 By Train + Bus (Recommended for Non-Drivers)
Take the JR Chuo Line limited express “Azusa” or “Super Azusa” from Shinjuku Station to Matsumoto Station (approx. 2.5–3 hours). From Matsumoto Station’s bus terminal, board an Alpico Kotsu bus bound for Norikura Kogen / Sawando via the Shirahone Onsen line (approx. 1 hour 15 minutes) and get off at the “Shirahone Onsen” stop, a short walk from the inn. Buses are limited in number, especially outside peak season, so check the timetable in advance.
🚗 By Car
Exit at Matsumoto IC on the Nagano Expressway (approx. 60 minutes to the inn) or Takayama IC if approaching from the Gifu side (also approx. 60 minutes). The final stretch is a winding mountain road — winter tires or chains are essential from late autumn through spring.
| Route | Tokyo (Shinjuku) → Matsumoto Station → Shirahone Onsen |
|---|---|
| Train | JR Chuo Line Ltd. Express “Azusa” to Matsumoto (~2.5–3 hrs) |
| From Matsumoto Station | Alpico Kotsu bus to “Shirahone Onsen” stop (~1 hr 15 min) |
| Total from Tokyo | Approx. 4–4.5 hours door to door |
| JR Pass | ✅ Shinkansen/limited express portion to Matsumoto covered (local bus not included) |
| Winter Driving | ⚠️ Winter tires or chains required on the approach road, late autumn–spring |
A Quiet Corner of Nagano’s Alpine Heartland
Marunaga Ryokan sits right in the small hot spring village of Shirahone, within easy reach of some of Nagano’s best-known natural scenery. The Funtokyu mineral formations, a nationally designated natural monument created by centuries of dissolved calcium carbonate hardening into rock, are a short walk from the inn — a striking large-scale example of the same mineral process that has shaped the ryokan’s own private bath. Kamikochi, one of Japan’s premier highland scenic areas, is roughly 50–60 minutes away by car and shuttle bus, while the Norikura Kogen highlands, with their waterfalls and cool alpine air, are about 20 minutes by car.
The Rooms
| Toilet | En suite (in-room) |
|---|---|
| Refrigerator | Available |
| Air Conditioning | Not available |
| Wi-Fi | Available |
| Television | Available |
| Towels & Yukata | Provided |
Left: An 8-mat tatami room with an attached wide veranda. Right: The deep veranda made for a pleasant spot to sit and take in the mountain air.
Rooms here are simple and comfortable rather than luxurious — a small television, a refrigerator, and an en-suite toilet cover the essentials, and the wide veranda adds a bit of extra space to relax in. There’s no air conditioning, which is rarely an issue given the elevation, but worth noting for a summer visit.
The Hot Springs — Two Milky Sources, Very Different Characters
Marunaga Ryokan offers a gender-separated indoor bath, a mixed-gender outdoor bath, and a private bath — three very different ways to experience Shirahone Onsen’s famous milky water.
The indoor bath and mixed-gender outdoor bath draw on the Shin-Awa-no-yu source, which flows at a generous 1,893 liters per minute and is gently heated before use. The private bath instead uses the separate, low-temperature Konashi-no-yu source. Both are sulfur-bearing bicarbonate springs, and both produce the pale, milky-white water and faint sulfurous aroma that Shirahone Onsen is known for nationwide.
The Indoor Bath — Reliably Warm, Cypress-Scented
Fed by the Shin-Awa-no-yu source, the indoor bath is a quiet, cypress-scented room that runs around 40°C — comfortably warm and the easiest of the three baths to fully relax in. Mineral deposits build up visibly around the tap, and the water is drinkable, a small detail some guests enjoy trying for themselves.
The Mixed-Gender Outdoor Bath — Lukewarm and Nearly Impossible to Leave
Left: The outdoor bath’s milky water carries a faint bluish tint. Right: An open view of the surrounding trees and mountains from the bath.
Reached directly through a door from the indoor bath, this outdoor pool is Marunaga’s signature feature — and it’s kept noticeably cooler, around 37°C. In the cold winter months especially, it runs gentle enough that you can comfortably stay in for a very long time without overheating; the water near the spring inlet runs slightly warmer, and that’s where most guests tend to settle in. On snowy days, with flakes drifting down over the milky, faintly blue-tinted water and forested hills all around, and lanterns lighting the bath after dark, it’s easy to see why this is the highlight of a stay here.
♨ About Mixed-Gender Bathing (Konyoku) Here
Guests may wear a bathing wrap or rental towel in the outdoor bath, and women have their own separate entrance into the same pool — both details that make it considerably more approachable than mixed baths requiring full nudity. Combined with the milky water, which naturally obscures visibility, this is a relatively easy introduction to konyoku bathing for first-timers.
The Private Bath — A Tub Fused to the Floor by Decades of Mineral Growth
Left: The private bath, fed by the separate Konashi-no-yu source. Right: Thick white calcium deposits have built up along the rim and floor over many years of continuous use — a striking, almost sculptural effect.
This bath isn’t listed on the inn’s official website and is easy to miss, but it’s arguably the most memorable spot in the building. Fed by the low-temperature Konashi-no-yu source, it shares the same milky-white sulfur character as the other baths — but here, years of mineral-rich water flowing continuously over the tub’s edge have left thick white calcium deposits that now blend the tub, the rim, and the floor into a single continuous, almost organic form. It runs a little warmer than the outdoor bath, so it’s worth watching for lightheadedness on a long soak. A wooden cover over part of the tub helps retain heat, and a separate washing area is provided.
Dining — Light, Home-Style Cooking
Meals lean healthy and unfussy, built around river fish and mountain vegetables rather than heavy, rich dishes — a good match for the gentle, restorative feel of the springs themselves. Dinner is served from 18:00, breakfast from 7:30.
The evening meal features dishes distinctive to the region — sweetened simmered carp (koi no kanroni) and sashimi among them — alongside salt-grilled river char with nicely crisp skin, mild Shinshu buckwheat noodles, and grilled wild boar.
Left: Breakfast follows the same gentle, non-greasy approach as dinner. Right: A comforting rice porridge (okayu), easy on the stomach and warming after a night of soaking — the standout of the breakfast table.
Breakfast follows the same gentle approach, built around a comforting rice porridge that pairs well with the previous evening’s soak, finished with a simple regional touch: fresh Nagano apple.
Final Thoughts
Katsuranoyu Marunaga Ryokan doesn’t try to impress with scale or polish — its appeal is quieter than that. A lukewarm mixed bath you genuinely don’t want to leave, a private bath shaped by decades of mineral growth into something close to natural sculpture, and cypress-scented indoor baths all draw on Shirahone Onsen’s distinctive milky water in their own way. For travelers who want to slow down and simply sit in good water for a while, this is a place built exactly for that.
Katsuranoyu Marunaga Ryokan is ideal for visitors who:
- Enjoy a properly lukewarm bath for long, unhurried soaking
- Want to try mixed-gender bathing with the option to wear a bathing wrap
- Appreciate milky, mineral-rich sulfur springs in an authentic mountain setting
- Are visiting as a couple and want a private bath to themselves