photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

Architect: Kotaro Ide // ARTechnic Japan

Location: Karuizawa, Nagano // JAPAN

Project Type: Private Residence

Assistants: Moriyuki Fujihara, Ruri Mitsuyasu, Takashi Mototani (former member), Kenyu Fujii

Collaborator: Manami Ide (designer of customized metal work)

Structural Engineer: Naomi Kitayama / NAO

Mechanical engineer: Hiroshi Nakayama / TNA

Electrical Engineer: Jyunetsu Satou / EPS

Contractor: Kenji Kusunoki / GIKAKU

Date of Completion: 2008

Structure: Reinforced Concrete

Site Area: 1,171 square meters

Total Floor Area: 329 square meters

Photographer: Nacasa & Partners Inc.



photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

Interesting architectural design approaches, are always interesting no matter when they were presented for the first time. One such interesting architectural design is the “Shell” residence by Japanese Architect, Kotaro Ide of ARTechnic. The project concluded its works in 2008; the sculptural shell-like structure was built in the forest of Karuizawa, located in the Nagano prefecture of Japan.

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

This large two-storey shell-shaped structure makes itself distinct from the surrounding caves and rocks, and it is clearly not a part of nature. However, its organic shape seems subtle within the forest, and the reinforced cement structure becomes one and harmonizes itself with the landscape. The principals desired a residence which will be occupied as a vacation home, with frequent visits and to be used for many years to come. Whatever the design of the residence would be it had to co-exist with nature. “The existence of the structure depends on its power to endure nature.” A clear distinction of the spaces [structure vs. nature] upgrades the quality of the residence as a shelter; the house will be sheltered from nature and utilize what nature can offer. Moreover, with such a design the residence will be used often and integrate through its use with the surroundings.



photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

The low temperatures in Karuizawa along with the increased humidity levels make for a harsh climate. As a result many houses in the area with a traditional structure and construction are facing overwhelming decaying problems. With this in mind the architect came up with a large shell structure which floats above the ground and is constructed by reinforced concrete. Taking example from other villas of the nearby area which have not been used for many years, Kotaro Ide tried avoiding the common structure and materials used in the construction. The use of reinforced concrete for the residence will assist the residence in protecting itself from the high humidity levels and the cold.



photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

The exterior of the “Shell” residence is wrapped in the shell-like concrete structure finished with a penetrative sealer for concretes, which contrasts with the green landscape. Deck wood is used on the patio, while a small amphitheater-like structure has been created in the center of the house around a full-grown tree. Large double glazed openings allow for uninterrupted views of the nature from within the house.

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

The interior architectural design of the residence follows the exterior form of the house; the walls are curved and have not been straightened. Instead features and furniture within the residence have been custom-made to meet the design requirements of the original structure. The architects paid careful attention to the design details for the comfort and the performance level of the residence.

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

Cherry hardwood flooring is used throughout the residence, while oak has been used for some furniture which makes a lovely contrast with the flooring. Many furniture items have been custom designed as the shape and the structure of the walls makes it hard for regular furniture to fit in ideally. The communal spaces have been given use on the ground floor while the private spaces such as the bedrooms are located on the upper level.

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

A custom-made floor heating system minimizes the loss of heat from within the house, and assisted in creating large openings. This custom-made heating system works as a cold-draft blocking system which enables the luxury of enjoying a hefty amount of space with large openings. The system integrates itself within the architectural form. “The central control system enables all mechanical and electrical equipments to be managed by three buttons. In addition, the biometrics lockage and security system will reduce anxiety and stress over house safety management.”



photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

Overall, the Shell residence has a simple aesthetic design which blends itself well to the traditional Japanese landscape, as it creates a balance between the futuristic man-made structure and the environment which surrounds it. The entire project took more than eighteen months to realize and two and a half years to complete.

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan

photo (c) Nacasa & Partners Inc., Image Courtesy of Kotaro Ide // ARTechnic Japan