House in Kai is a minimalist residence located in Yamanashi, Japan, designed by MAMM DESIGN. The only strong request from client was that all rooms should be oriented to the south. Kai-city, a region with harsh winters, is in Kofu basin, which is centrally located in Japan. According to site regulations, it is possible to stack all rooms vertically, and build a three-story house. However, the architects did not think it was a good solution since it would weaken relations among family members who would occupy each floor separately.