elliptical residence by unformed design for NOT A HOTEL rises from japan's rocky hills

Unformed Design unveils design for not a hotel house in japan

Unformed Design introduces Nature Within, a residence that embraces dramatic rock formations and forested terrain in its architectural concept. Set to break ground in 2026 in Kitakaruizawa, Japan, the project transforms the natural landscape into a fundamental part of the design. This approach earned Unformed Design first prize in the NOT A HOTEL international design competition for architects and creators under 40.

Rather than treating the rugged terrain as a challenge, Unformed Design embraces it as the foundation of their concept. The residence incorporates weathered rock formations as structural and aesthetic elements, leaving them in their original positions to preserve the integrity of the site. These rocks form the foundation and support key areas of the home, eliminating the need for artificial bases. Nature Within’s form follows the natural slope of the land with an imperfect elliptical form that mirrors the contours of the terrain. This organic geometry allows the structure to nestle into the site, giving the impression that it has emerged naturally from the earth. The pitched roof extends beyond the walls, forming sheltered outdoor spaces that transition into the landscape, while a rear terrace hugs the terrain to provide a private retreat immersed in nature.

images courtesy of Unformed Design and NOT A HOTEL

rock formations anchor the interior of nature within residence

Inside, the rocks become central to the layout by the Milan-based practice Unformed Design. Their raw, textured surfaces serve as partitions and visual focal points, grounding the architecture in its surroundings. These formations also act as load-bearing elements, reducing the need for conventional structural systems while connecting the residence to the land.

The lower facade features expansive glazing, framing views of the forest. In the open-plan living and dining area, the rocks anchor the space, while private areas, including bedrooms and a sauna, are positioned for intimacy. The result is a home with spaces that echo the sheltering quality of natural caves.

The material palette balances rugged textures with refined finishes. Dark wood clads walls and floors, while sleek industrial metal accents adorn the kitchen and fireplace. Large glass surfaces bring the forest and rock formations into the home, ensuring nature is ever-present. The thermal properties of the rocks also help regulate indoor temperatures, enhancing the energy efficiency of the NOT A HOTEL’S future property.

a residence that embraces rock formations and forested terrain in its architectural concept

set to break ground in 2026

the material palette balances rugged textures with refined finishes

large glass surfaces bring the forest and rock formations into the home

ensuring nature is ever-present

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site plan

axonometric drawing

floor plan

project info:

name: Nature Within
architect: Unformed Design | @unformedesign
location: Kitakaruizawa, Japan

client: NOT A HOTEL | @notahotel_official

designboom has received this project from our DIY submissions feature, where we welcome our readers to submit their own work for publication. see more project submissions from our readers here.

edited by: thomai tsimpou | designboom