The site is located in Kamakura, one of the ancient city of Japan. Y house is a house for a couple and their three children.The surrounding can be characterized by gabled roof low rise houses built in high density with lush greenery, narrow street with hedge and clayey wall. Y house is considered as a continuous space to this ambient context supported by treelike structure.We consider Y house as a case study, an application of more general system that spread columns and their density defining the space. However, in contrast to modern architecture models that is more universal in all direction, this system is pursuing an architecture that blend and respond to ambient context, or gravity.