This building is a painter’s studio, built as an annex of his villa in a provincial city, approximately a two-hour drive from Tokyo. The site is a leveled ground supported by retaining wall on a gently inclined natural slope facing south. Creating contrast to the villa simply placed on top of the flat land, we dug up the ground to create the “third terrain” and internalized the ground to secure a space for the studio. The floor, modeled after the terrain, is a combination of wood masses cascading down from the surface of the leveled ground and forming a main work space as it reaches the original ground level. At a glance, the plan and section appear to have been designed in a random manner, as if imitating the natural terrain, but they are actually indicating a basic orientation of the centripetal architectural space based on a tendency that painters generally work at the center of the space surrounded by art supplies and other miscellaneous things in their studios. The terrain was the key to designing this centripetal open space. Several platforms surrounding the central work space, as well as a number of steps to put miscellaneous things, were planned as if they had been carved out from the solid earth used for land grading previously existed here. The paradoxical approach of “construction by subtraction”, not by addition, was carried out, and the conceived space was covered with a simple one-story wood frame shed. The hexagonal plan was formed by cutting corners of a square to provide views through the space and out, while creating an outer frame orienting the interior space towards the center at the same time. Since a sufficient spatial volume was secured by excavating the ground, the roof and the shed were kept low and flat. The black and abstract exterior of the studio creates a vivid contrast to the raw materiality of the log villa in the overall scenery. Looking into the interior, the modern horizontal plane composed of equally-arranged roof joists and the undulating “terrain” conceived by the primary architectural action of digging conflict with each other, and the studio is inserted into the space in between. The painter creates abstract paintings using the method of Japanese painting: he paints small pieces on the floor, and then lays them out to constitute a single large piece of work on the largest wall hung from the structure. The artist paints at the center of the space surrounded by numerous things stacked three dimensionally on undulating surfaces of the “third terrain”; in this space, the “terrain” mediates between humans and things.