Senri Civic Center is a compound community service building designed by Fumihiko Maki in 1968, which embodied two of his essential concepts––Urban Room and Group Form. A multifunctional transparent space becomes a gathering place for citizens on the ground floor, with an extrude boundary shape that allows interior and exterior to penetrate. At the center of the building, the famous group form was embodied in replacing one gigantic core with a core bundle composed of five similar shapes. Meanwhile, it also opens the corner of the building. Maki has always been called an “urban designer” because of his insistence on taking architecture as a component of the urban environment, paying attention to the overall effect of the environment and applying urban design techniques in architectural design. Our doubling consists of three parts: empty the original building to create a void as a larger urban room; insert similarly shaped cores to Maki’s group; and duplicate in the size of the original building vertically.