Japanese squares were originally ambiguous spaces where freedom and regulation coexisted. During the Edo period, such places as kaijoji were managed by the local community, but residents were allowed to use them freely. With modernization, however, excessive regulations were set and freedom was lost. Not only plazas, but also public spaces and facilities have lost their ambiguity due to excessive regulations. On the other hand, ambiguous spaces have recently emerged, such as the Shibuya Halloween, where certain freedoms of young people are allowed while regulations within the society are kept at the same time. This proposal explores the coexistence of freedom and regulation, and using the plaza in front of the Imperial Palace as the target site, proposes an ambiguous space where "created freedom" and "freedom to create" exist independently but coexist by combining geometric shapes obtained through research and analysis.