The purpose of this paper is to clarify the relationship between Buddhism and Kyosei, some concrete examples of the cooperation between religions in Japan, and the deciding factors in causing Kyosei between religions. Kyosei is a commonplace expression not only in a religious world but also in a secular one. WCRP is one of the most famous model of Kyosei in Japan. The factors of Kyosei are needs in the society, an ecumenical theology, a structure of leadership and a cohesive society, and a major religious power.
