Wonderwall® Designs a Forest Retreat for NOT A HOTEL KITAKARUIZAWA

NOT A HOTEL KITAKARUIZAWA has unveiled MASU, a new forest retreat designed by Masamichi Katayama-led Wonderwall®, where the restraint of Japanese architecture meets the clarity of mid-century modernism.

Built around the concept “Suki ni sumu” (As you like it), the project takes inspiration from architect Kenzo Tange’s 1953 residence in Seijo, reinterpreting its dialogue between traditional Japanese spatial thinking and modernist structure for contemporary living. At its core is a modular system of eight 4 x 4-meter “masu” on the upper floor, framed by a steel structure and a continuous 360-degree deck that dissolves the boundary between the home and North Karuizawa’s surrounding woodland. Below, a pilotis opens the dining area toward an outdoor living space and fire pit, while a light cantilevered staircase cuts through the double-height atrium, allowing daylight and air to move freely between levels.

Inside, Wonderwall® approaches the residence less as a uniform interior than as a carefully assembled conversation between East and West, vintage and contemporary. Warm timber ceilings, expanses of glass and restrained architectural surfaces are offset by richly tactile elements, including custom furnishings designed specifically for MASU and a selection of mid-century classics.

Isamu Noguchi’s sculptural Akari lighting illuminates the atrium, while pieces including George Nakashima’s CN108 Bench, Eero Saarinen’s Womb Chair and stools by Jean Touret appear throughout. Mika Tajima’s Negative Entropy, which translates sound data into jacquard-woven imagery, adds another layer to the living area, while deep carpeting and low-slung seating give the otherwise disciplined geometry a softer, almost sunken lounge-like character. The result is deliberately composed without feeling overly pristine, balancing the precision of the architecture with the comfort and individuality associated with the Japanese notion of suki.

That relationship with the landscape becomes most pronounced in MASU’s more private spaces. Floor-to-ceiling windows make the bedrooms feel suspended among the trees, while one entire 4 x 4-meter module is devoted to a bathroom equipped with a natural hot-spring bath and cold plunge, connected directly to an adjoining sauna and the wraparound deck for open-air cooling.

Outdoors, a fireplace-centered living area is intentionally left open-ended for dining, reading or gathering around the fire, while each of the four houses incorporates its own distinctive additional “masu,” configured variously as a tea room, Japanese-style room, study, theater or bedroom. Spanning over 526 square meters of combined indoor and outdoor space, MASU officially open for booking through NOT A HOTEL KITAKARUIZAWA.

NOT A HOTEL KITAKARUIZAWA
Tsumagoi Village, Agatsuma District,
Gunma Prefecture, Japan