Dezeen Magazine

Inbetween House by Koji Tsutsui Architect & Associates

This house in a mountain region outside of Tokyo by Koji Tsutsui Architect & Associates is composed of five connected cottages.

Inbetween House by Koji Tsutsui Architect & Associates

Each of the larch-clad cottages of Inbetween House varies in size and has a different single roof pitch, with overhangs that overlap one another to create connections internally.

Inbetween House by Koji Tsutsui Architect & Associates

The buildings have a fan arrangement on site that adds further variation to the shape of the interior spaces, from which there are wide views of the surrounding landscape.

Inbetween House by Koji Tsutsui Architect & Associates

Photography is by Iwan Baan

Inbetween House by Koji Tsutsui Architect & Associates

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Here are some further details from the architects:


The client chose the sloped site surrounded by Japanese larch trees and located in a mountainous region, an hour away from Tokyo on a bullet train, as their ideal location for their home where they can retreat from their busy work in the city.

Inbetween House by Koji Tsutsui Architect & Associates

The house sits on an artificially leveled area of the site created thirty years ago and left unused. Since the client wanted a house seamlessly blend into the natural surrounding, topography and local culture, we designed this house as a collection of small mountain cottages.

Inbetween House by Koji Tsutsui Architect & Associates

It consists of five single pitched roof cottages that are clad in the local larch wood siding. Rather than using a complex construction technology, it is built in a traditional Japanese wood construction method so that local builders can skillfully craft each structural wood member. Each cottage varies in size to fit its function and set on site at 30 degree increments to best fit the topography and to face unique views.

Inbetween House by Koji Tsutsui Architect & Associates

All cottage roofs have varying slopes and overhangs that touch the overhangs of adjacent cottages, creating gap spaces between these cottages, a simulacrum of alleys in a city. The triangular “connecting” roofs span between these overhangs to capture these gap spaces as a single fluid public interior space, which serves as a living room or a circulation space and feels like being outside looking at mountains in the distance. Since these connecting roofs bend & fold to connect the cottages at multiple angles & heights, the in-between space results in a spatial & structural warpage.

Inbetween House by Koji Tsutsui Architect & Associates

The design intent of this house is not the final architectural form, but rather, establishing a set of design rules of cottage placements and connections, which allows the house to be freely arranged to satisfy any requirements and adoptable to any future changes or additions, prolonging its building life.

Inbetween House by Koji Tsutsui Architect & Associates

Place: Karuizawa, Nagano, Japan
Architect: Koji Tsutsui Architect & Associates, Koji Tsutsui, Satoshi Ohkami
Structural Engineers: ANARCHItects(CG), Hirotsugu Tsuboi
General contractor: Sasazawa Construction, Inc.
Photographer: Iwan Baan
Site Area: 1956.16m2
Floor Area: 178.43m2
Completion Year: 2010