KAI, a leading onsen ryokan brand by Hoshino Resorts, is set to open KAI Kusatsu in Kusatsu Onsen, Gunma Prefecture, on June 7, 2026. The property introduces a new accommodation experience that links the lively hot spring town with a serene inn through an exclusive guest-only tunnel, expanding options for guests during their stay. Extended stays allow guests to immerse themselves in Kusatsu’s rich culture, local cuisine, and seasonal scenery. Signature “Silk Art Rooms” showcase Gunma’s silk and weaving heritage, while the public baths feature two types of highly acidic hot springs, including the renowned Bandaikou source. Dining options include traditional kaiseki meals highlighting Joshu cuisine or the newly established "Soba Kappo SAI," located on-site.
About KAI Kusatsu
The concept of KAI Kusatsu is "An Onsen Ryokan Amidst the Trees Featuring a Private Tunnel." Located on a hill at the base of Mount Kusatsu-Shirane, one of Kusatsu’s iconic landmarks, the property is surrounded by lush nature. The main accommodation building offers 94 guest rooms, complemented by a tree-framed central courtyard, a separate bathhouse, and a lounge. Guests can enjoy a tranquil stay, whether soaking in the baths or simply relaxing in the serene environment. A standout feature is a guest-only tunnel connecting the ryokan directly to Kusatsu’s hot spring town. Emerging from the tunnel, guests are just steps from Nishinokawara Park, known for its open-air baths, making visits to the Yubatake area and nearby streets easy. This exclusive link allows guests to move freely between the peaceful retreat and the lively, historic town, experiencing Kusatsu’s charms to the fullest.
Experience Kusatsu on an Extended Stay
Easily accessible from the Tokyo, Kusatsu Onsen is a year-round destination with a wide range of attractions. KAI Kusatsu highly encourages extended stays (two nights or more) to fully explore the region. The property is conveniently located just a three-minute walk from Kusatsu Onsen Ski Resort, and the area offers abundant seasonal activities such as golf, scenic touring, fresh greenery in spring, and autumn foliage viewing. Leveraging the property’s unique features, including the guest-only tunnel, KAI Kusatsu plans to offer a variety of extended stay programs that connect guests with the local area, providing deeper engagement with Kusatsu’s culture, nature, and history.
Features of KAI Kusatsu
1. KAI Signature Rooms: “Silk Art Rooms,” Inspired by the Soft Texture and Elegance of Fabric
Each KAI property features locally inspired Signature Rooms that reflect the essence of the region’s culture. At KAI Kusatsu, the “Silk Art Rooms” pay homage to Gunma’s rich history of silk production. The centerpiece is a woven textile artwork depicting Kusatsu’s mountain landscape and rising onsen steam, expressed through delicate color gradations and fine silk threads. Designed by internationally acclaimed textile artist Reiko Sudo and crafted with Kiryu’s traditional weaving techniques, the rooms blend artistry with comfort. Silk lampshades, cushions, and bed runners inspired by alpine flora complete a soft and harmonious atmosphere throughout the room.
<Textile Designer: Reiko Sudo>
Profile
Born in Ishioka, Ibaraki Prefecture. Representative of NUNO Corporation and Honorary Professor at Tokyo Zokei University.
Reiko Sudo is known for her innovative textile creations that blend Japan’s traditional dyeing and weaving techniques with cutting-edge modern technology. Her works are part of the permanent collections of major museums around the world, including the Museum of Modern Art (MoMA) and The Metropolitan Museum of Art in New York, the Museum of Fine Arts, Boston, the Los Angeles County Museum of Art (LACMA), the Victoria and Albert Museum in London, and the National Museum of Modern Art, Tokyo.
Comment
“The Joshu region of Gunma Prefecture has long flourished as a textile hub, known for its silk industry—including sericulture, spinning, weaving, and embroidery. Even today, it remains a treasure trove of materials, skills, and craftsmanship that continue to inspire creators both in Japan and abroad. Throughout KAI Kusatsu, you’ll find textiles designed by NUNO, inspired by the natural environment and history of the Kusatsu region. Our team placed great importance on local character, making extensive use of Gunma-produced materials and techniques while pursuing sustainable practices in yarn and fabric production. For this project, more than twenty local artisans and businesses contributed their wisdom, skill, and craftsmanship to bring this textile space to life. I hope guests will feel the depth of that collaboration during their stay.”
2. Hot Springs: Two Distinctive Acidic Springs from Kusatsu Onsen
Kusatsu Onsen boasts Japan’s largest natural hot spring output, with over 32,300 liters of water gushing per minute. At KAI Kusatsu, the public baths draw from two distinctive acidic hot spring sources to let guests fully enjoy this abundant water. One source is Bandaikou, known for its high volume, high temperature, and strong acidity, while the other is the rarer and milder Sainokawara source, accessible at only a limited number of facilities. The indoor baths feature three separate tubs, allowing guests to enjoy a “hot spring tour” experience with different water qualities and temperatures. Large windows offer expansive views of the central courtyard, creating a relaxing space to savor the unique waters of Kusatsu Onsen.
3. Dining: Flexible Options to Suit Your Stay
Joshu Houden Kaiseki at the Main Dining Room
Guests can enjoy a kaiseki dinner in a semi-private dining space, highlighting the flavors of Gunma. The multi-course “Joshu Houden Kaiseki” begins with an appetizer inspired by Kusatsu’s Yubatake and Yumomi traditions, and features seasonal local ingredients. The main dish, “Joshu Joyo Nabe,” is a hot pot with whole simmered chicken thigh and Gunma spinach, served in a savory broth, perfect for a leisurely, immersive dining experience.
Soba Kappo SAI on Site
A new dining option within KAI Kusatsu, Soba Kappo SAI specializes in 100% local buckwheat noodles with a flavorful dipping sauce made from bonito, kombu, and dried shiitake. A variety of small dishes complement the soba, and local sake, craft beer, and natural wine are available. This lighter, casual option broadens dining choices during your stay.
Property Overview
Project Overview
About KAI
KAI is Hoshino Resorts' onsen ryokan (traditional Japanese hot spring inn) brand well loved by local and overseas travelers. With 23 properties across Japan, KAI aims to provide hospitality that meets modern needs while preserving the beauty of the seasons, Japanese aesthetics, locality and traditions of the different regions. KAI Cultural Discovery, a key feature of the brand, offers guests experiences of local traditional culture and crafts, while KAI Signature Rooms (guest rooms) are designed to reflect the unique culture of each region. In 2026, KAI plans the opening of three new facilities: KAI Kusatsu (Kusatsu Onsen, Gunma Prefecture), KAI Miyajima (Miyajima Onsen, Hiroshima Prefecture), and KAI Zao (Zao Onsen, Yamagata Prefecture), as well as the renewal of KAI Matsumoto (Asama Onsen, Nagano Prefecture).
Best Rate Guaranteed
