As a typical site in central Tokyo with high density, the site is surrounded by neighborhood building with only one side facing the road on the west. The aim of this design was taking in the natural environment hidden behind an artificial city. As to the configuration, large space was stacked at the bottom and small one in the upper part creating the continuous semi-outdoor space. Then the whole building was wrapped with porous shades to let the semi-outdoor space be filled with moderated daylight and breeze. The change of the natural environment through a day brings workers the gentle rhythm.