In the spring of 2026, Hoshino Resorts' hot spring ryokan brand, KAI, will open its 24th location in Kusatsu Onsen, one of Japan's three most renowned hot springs. Located high on a plateau at the foot of Mt. Shirane in Kusatsu, KAI Kusatsu is designed with the concept of "tunnel connecting forest hot spring lodges and hot spring town." Directly connected to Nishi-no-Kawahara Park via a dedicated underground tunnel, guests can experience both tranquil accommodations surrounded by rich nature and the vibrant history of Kusatsu Onsen.
This 94-room hot spring inn features a multi-building design, with accommodations, hot spring rooms, and social areas scattered around a lush courtyard. The Yubatake area is a mere five-minute walk from the tunnel, making it an extremely convenient location. As the KAI brand's first location in Gunma Prefecture, KAI Kusatsu will continue the brand's "authentic yet innovative" service philosophy, combining traditional local culture with modern comforts to create an unforgettable hot spring retreat experience.
Service Features and Brand Characteristics: Inheriting the spirit of the Royal Hot Spring Hotel and incorporating innovative design thinking
Hoshino Resorts' "Kai" brand, centered around the concept of "authentic yet innovative," has established a unique hot spring ryokan culture across its 23 locations nationwide. Each KAI ryokan deeply integrates local history, culture, traditional crafts, and local characteristics, allowing guests to experience the traditional arts and crafts of each region through "Local Music" activities. This service model not only maintains the traditional hospitality of Japanese hot spring ryokans, but also incorporates the needs and tastes of modern travelers, creating a unique accommodation experience that is both nostalgic and cutting-edge.
KAI Kusatsu will continue this brand spirit and plan to feature local experiences themed around the unique Yumomi culture of Kusatsu Onsen. Furthermore, the hotel's interior design will blend the natural landscape of the Kusatsu area with elements of its hot spring culture, with both the exterior and interior décor reflecting a respect for the local environment. The professional service team will leverage Hoshino Resorts' accumulated years of hospitality experience to tailor a personalized service experience for each guest, ensuring that guests enjoy the convenience of modern amenities while also experiencing the refined service culture of a traditional Japanese hot spring inn.
Room Types and Features: 94 meticulously designed guest rooms with stunning views of Mt. Kusatsu Shirane
| Room Type | 大小 | bed | Number of people |
|---|---|---|---|
| Standard Japanese-style room | Estimated area: 12-15 pings | Japanese tatami bed | 2-4 people |
| Deluxe Japanese-style room | Estimated area: 15-18 pings | Japanese tatami bed | 2-4 people |
| Japanese-Western-style room | Estimated area: 18-22 pings | Double bed + Japanese-style room | 2-4 people |
| Special Room | Estimated area: more than 25 pings | Double bed + separate living area | 2-6 people |
Each of KAI Kusatsu's 94 guest rooms will fully embrace KAI's "Local Room" design concept, incorporating elements of the culture and nature of the Kusatsu Onsen region. The building faces the courtyard, offering guests stunning views of the seasonal gardens and distant Mount Kusatsu Shirane. Rooms will feature modern air conditioning, high-speed wireless internet, and curated local crafts, creating a comfortable and culturally rich environment.
All guest rooms feature either their own private hot spring bath or high-quality modern bathroom amenities, allowing guests to enjoy the healing benefits of Kusatsu Onsen in the privacy of their own home. The furnishings and amenities within the rooms have been carefully selected, including furnishings crafted using traditional local crafts, comfortable bedding, and welcome refreshments featuring local specialties. Each room is designed with the diverse needs of each guest in mind, ranging from romantic spaces perfect for couples to spacious rooms ideal for families, ensuring that every guest will find the perfect accommodation.
Dining space and public facilities: Diversified facilities configuration to create a complete resort experience
KAI Kusatsu features a multi-building design, with facilities scattered around a lush green courtyard, creating a unique architectural cluster. The hot spring building will feature a variety of hot spring baths, including open-air baths overlooking Mt. Kusatsu Shirane, therapeutic indoor large baths, and smaller, more private pools. The lounge building offers comfortable relaxation spaces where guests can enjoy refreshments, read a book, or participate in local music and cultural activities.
The dining facilities will focus on showcasing the unique culinary culture of the Kusatsu region, utilizing fresh local ingredients to create dishes that balance traditional and innovative cuisine. The restaurant design will incorporate elements of the hot springs region's natural beauty, with large glass windows framing the dining environment and the outdoor landscape. Additionally, the facility will feature a dedicated local music experience building, hosting regular traditional Kusatsu cultural events such as Yumomi performances and local craft workshops. The shopping area will showcase a curated selection of Kusatsu hot springs specialties and souvenirs, allowing guests to take home cherished memories of their trip.
Transportation and the surrounding environment: Innovative design of dedicated tunnels perfectly connects nature and humanity
A key feature of KAI Kusatsu is its specially designed underground tunnel, connecting the hotel directly to Sai-no-Kawara Park in Kusatsu Onsen. This innovative design allows guests to explore the hot spring town at any time, regardless of weather conditions. The tunnel exit is a mere five-minute walk to the famous Yubatake (water bath), and other major hot spring facilities such as Ōtakinoyu and Sai-no-Kawara Open-Air Bath are also within walking distance, making its location extremely convenient.
Surrounded by abundant nature, the inn offers fresh greenery in spring, a cool highland climate in summer, vibrant autumn foliage in autumn, and the romantic atmosphere of snow-covered hot springs in winter. Just 200 meters from Kusatsu Onsen Ski Resort, winter sports enthusiasts can easily enjoy the area. The inn is also conveniently located, taking the JR line from Tokyo to Naganohara Kusatsuguchi Station, followed by a bus ride of approximately 30 minutes. The inn plans to offer a shuttle service to facilitate travel between the station and the accommodation.
Hotel basic information
| Accommodation name | KAI Kusatsu |
|---|---|
| Opening date | Spring 2026 (scheduled) |
| Appointment starts | Autumn 2025 (scheduled) |
| Tel | 050-3134-8092 (Kai Reservation Center) |
| Number of guest rooms | 94 |
| Official Website | Hoshino Resorts official website |
| Address | Kusatsu, Azuma-gun, Gunma Prefecture (Kusatsu Shirane foothills high platform) |
| Main facilities | Front desk, shop, dining area, bathhouse, social hall, local music hall, atrium |
