The author examines architectural theories that led to the founding of Bunriha Kenchiku Kai (Secessionist Architectural Group) in 1920, in line with four phases focusing on the understandings of “expression”. First of all, the notion of architecture was divided into “art” and “science/utility” when it was introduced to Japan from the West. Secondly, the “art” was relegated to a lower importance through Sano Toshikata’s nationalistic view of architecture. Sano’s follower Noda Toshihiko subordinated architectural design only to the theory of structural mechanics. Their understandings of “expression” were unilinear. Thirdly, Goto Keiji, Noda’s adversary in study, believed that principles of architectural design were to be rediscovered within architects’ selves: he became a predecessor of Bunriha. Moreover, a Bunriha architect Horiguchi Sutemi insisted on “life” and “faith” within one’s instinct. But their discussions deemed architecture only as reflections of the “self/life”. Finally, the integration of self and architecture took place when another Bunriha architect Morita Keiichi discovered “inner demand” in the “beauty of dynamics” of the building. However, his understanding of “expression” remained unargued due to the theoretical constraints by the surrounding architects. This has affected our view of Bunriha.