Soka Gakkai is one of the world’s fastest-growing religious movements and Italy figures among the western nations where this religious group has been most successful. This article aims at explaining this success-story: why has Soka Gakkai, and particularly its Italian affiliation, grown so rapidly in recent years? This research question gives the opportunity to assess the applicability of the economic theory of religion to the growth of new religious movements. Hence, in order to explain the expansion of Soka Gakkai, this (...) work begins with an examination of the adaptive strategies developed by a Japanese organization in the Italian religious market. It is claimed, however, that a rational choice explanation cannot stand on its own and that we must take into account the dynamics of pre-contractual solidarity that promote trust, especially when the expected benefits promised by this organization to its adherents do not materialize. Moreover, these solidarity dynamics generate intense emotional gratification that works as a highly motivating incentive to sustain members’ commitment and to prevent them from dropping out. This pre-contractual solidarity is actively produced and continuously reproduced by means of ritual interaction along the lines suggested by Collins’s theory. (shrink)