KAI Kusatsu (界 草津) has something almost no other ryokan can offer: a private tunnel connecting this nature-secluded property directly to the historic Kusatsu hot spring resort area. Guests can therefore bathe in both settings — the intimate baths of the ryokan and the lively public ones of the town.
Where KAI Kusatsu is
The address is 464-690 Shirane, Kusatsu, Agatsuma, Gunma — in the mountains of Gunma Prefecture, north-west of Tokyo. Kusatsu itself is one of Japan's three most famous hot-spring towns, and the ryokan sits back from the centre in a wooded setting. With 94 rooms and an occupancy of 1 to 4 guests, it is one of the larger KAI properties — the scale is deliberate, because the draw here is the town as much as the building.
Getting there
By car
Kusatsu is reached from Tokyo by road, climbing into the mountains of Gunma. An exclusive car-rental discount is available to guests. The road up is a proper mountain road — in winter, check conditions before setting out.
By train and bus
By rail to Naganohara-Kusatsuguchi Station, then the bus up to Kusatsu. The property also lists access from Haneda Airport for guests arriving by air.
The tunnel — the reason to choose this one
The private tunnel is the signature. It lets you walk from the seclusion of the ryokan straight into the middle of Kusatsu Onsen, where the Yubatake — the wooden channels that cool the steaming spring water — sits at the centre of the town. Kusatsu's water is famously hot and strongly acidic, and the town's bathing culture is public, social and centuries old. Having both is the point of staying here.
Rooms and dining
The rooms carry local silk art and murals — Kusatsu and the Agatsuma region have a textile tradition — and categories with a private outdoor bath are available. Dining is kaiseki-style, built around Gunma's mountain ingredients.
Frequently asked questions
Can I bathe in the town as well as the ryokan?
Yes. The private tunnel connects the property to the historic Kusatsu hot spring area, so both are accessible during your stay.
How many guests per room?
1 to 4 guests, across 94 rooms.
Is Kusatsu reachable from Tokyo without a car?
Yes — by train to Naganohara-Kusatsuguchi and then the bus; the property also lists access from Haneda Airport.
Planning a Gunma trip around it
Kusatsu works as the mountain night on a route out of Tokyo — Gunma's onsen towns, then onward to Nagano or Niigata. Every itinerary we build is designed from scratch around your dates and your group; there is no fixed departure and no group to join: have a Gunma itinerary designed for you — free, no obligation.
We plan private journeys for travellers worldwide, in any destination. Nothing about our trips is off-the-shelf.
For live availability and rates, see KAI Kusatsu on Trip.com. To ask a person, message us on WhatsApp — we usually reply the same day.
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