The wooden shell structure realizes one horizontal wide opening without any columns, and it creates “Observatory house”, where a family can enjoy marvelous scenery in a daily life.” This house is built in the hill in Matsuyama city, and we aimed to create a house that is the most suitable for the features of site. While the main structure of this house is wooden structure, we invented the wooden shell structure and created huge openings with removing columns. The wooden shell is composed of SPF lumber and structural LVL (Laminated Veneer Lumber), and each component is connected with making curved triangle lattice. Its detail is carefully designed as simple as possible. In this house, the contrast of bold edition and sophisticated detail also creates originality and depth of the space.