Building 15 of Sophia University's Yotsuya Campus is based on the theme of "turning the city into a forest," and aims to contribute to achieving the SDGs and realizing a carbon-free society, as well as to become a sustainable landmark for the region. It opened in the fall of 2022 as a base for adult education and community interaction. The three-story wooden building was designed and construction by Sumitomo Forestry, and is a fire-resistant structure. The main structural parts are made of "Kigurumi FR®," an original pure wood fire-resistant laminated lumber made from cedar from Tama. The facade, which is covered with crisscrossing wooden lattices, is concept design to express "diversity," "interaction with others," "truth," and "tradition," which are linked to Sophia University's founding principles. The first floor will operate a cafe that is open to the public, and as part of community contribution activities, the space will be provided to nearby neighborhood associations as a disaster prevention warehouse. The second and third floors are also used as classrooms for the "Professional Studies" course for working adults. We were responsible for design, layout, and construction of the third floor, which is used as a classroom for working adults. We aimed to create a space that would be a place to gather, learn from each other, and talk, and to foster concept design. We also linked the story of the architecture to the materials that make up the space, using Nishikawa timber (cedar and cypress) from Hanno, which, together with materials from Tama, helped build the city of Edo.