The site of the house is located in Takayama village, Gumma. It situated on a mountainside, an area which experiences winters of -10 and cool summers. Surrounded by mountains, the scenery is rich in nature. The house was planned as a second home and the client's country escape. The client, who lives in Tokyo, studied forestry at university and wished to utilize the local woods and natural energy sources available in the design. We wanted to efficiently harness sunshine and air within the house as natural energy. A large south-facing opening in the house brings in the warm rays of the sun in winter, which are then efficiently transformed into heat through reflection on the black flooring and retention within the super-insulated structure. The opening also has an eave and a wing wall facing west that keeps out the summer sun and/or afternoon sun and acts as a wind-catcher, taking in cooler air in summer. The main living space lies within a large open plan space. The ground floor can accommodate a large group of people, with a kitchen and work room built around a living-dining room with an open ceiling. On the first floor, a bedroom and a guest room are located, surrounding the open ceiling to create an integrated space. Each room also forms part of the integrated space in terms of the thermal environment through slits and movable partitions that allow a flow of air in and out, providing natural energy for each room. The architectural design that brings in sunshine and air effectively gives a spiral form to the house through an outdoor terrace that provides an opportunity for neighbors to socialize. This spiral form ‘rolls up’ several living spaces, just like a Sushi roll (Norimaki in Japanese), which combines vinegared rice rolled in a sheet of dried seaweed. Like a much loved Norimaki in traditional Japanese cuisine, we sincerely hope that the Norimaki-house, which combines modern design and the natural environment, will be loved by the public.