It is a large shell-shaped structure in the middle of the woods, perfectly integrated into nature. Within it one finds constructed floors, walls that separate spaces, and furnished rooms. The natural scenery conjures up a kind of sci-fi film image, in which locals inhabit an abandoned spacecraft. With time, trees will start to grow and encircle the spacecraft, harmonising it into the landscape.

Being in sync with nature isn’t about yielding to nature – it’s about coexistence. The structure’s existence depends on its power to endure nature. By isolating living space from the wilderness, and upgrading its quality as a shelter, the house will be protected from nature and will provide a comfortable environment to be used frequently and continuously.

We paid the utmost attention to the comfort and performance level of the house because shorter visits call for shorter maintenance times. In fact, the advent of Shinkansen high-speed railways has meant that it now takes just an hour and ten minutes to reach Karuizawa from Tokyo, with the result that weekend visits to the country have become a normal occurrence today. The house’s central control system – which is perfectly integrated into the architectural form – enables all mechanical and electrical equipment to be managed via three buttons. The installation of a custom-made floor-heating system minimises the use of heat energy and also avoids the trouble of having to empty radiator drainage systems in cold regions. Furthermore, it is a highly effective way of preventing mould formation as well as working as a cold-draft blocking system.

The regions’ low temperatures and high humidity make for a harsh climate. As a result, many houses with traditional structures are decaying. Despite the general avoidance of concrete as a building material in the region, its usage, along with the strategy of raising the house above ground level via a lifting structure, has helped to protect the building from humidity. To provide efficiency during maintenance, the concrete was left exposed and finished with a penetrative sealer.

In the style of many modern sculptures, we aimed to enhance the surrounding nature by incorporating it into the spatial structure. The idea was to build the villa around the big fir tree at the centre of the site, with a row of pine trees as the main view. Initially, we had planned to build a shell structure with three-dimensionally curved surfaces; the C-shaped section was to surround the fir tree and the plan of the building was to resemble the letter J. In addition, certain parts were set aside to hold double- volume spaces. However, when going over the budget, construction method and finish, the plan was revised down to a shell structure with two-dimensionally curved surfaces. The J-shaped structure is made of two different sized oval cylindrical masses cut with curves. The straight part of the J, a smaller mass, connects to the curved part of the J, which is a larger mass. At the top of the oval-shaped building the wall is 350 millimetres thick, and its width continuously increases to 750 millimetres as it descends towards the ground on both sides to meet structural requirements. The free-curved lines appear on the edge, and the three-dimensionally curved surface with a twist partly appears on the cut surfaces. The floor is built 1,400 millimetres above the ground, with the lower half of the shell structure greatly protruding towards the outside, supporting the terrace of the same height. All air and exhaust outlets are installed beneath the sash, letting air run outside through the terrace louvre. In addition, by devising unfixed windows, we tried to maximise natural ventilation (we haven’t installed air conditioning in general parts). While at a glance, the oval-shaped cylinder space might appear as a wasteful use of space, the functional use of space is maximised by the installation of furniture in the lower half of the oval cylinder.