This is a renovation project of an apartment in East Tokyo. Japanese renovations entails maintaining the central part of the house, the Washitsu but modernizing the rest of the house with the latest equipment to provide comfort. Washitsu is a spiritual space, totally a no-shoes zone and no furniture. Sitting is on the tatami(woven) mat. Washitsu is designed based on the Japanese module of 910mm grid mainly for wooden structures. Fitting this modeule in the RC apartment was a challenge but rewarding seeing how such a traditional space can embed in a ultra modern setting.