Regardless of his own stated purpose or expected outcome for the Rissho ankoku ron, one of Nichiren’s accomplishments in writing this treatise was the articulation of a canon, that is, a list of texts that were deemed true and authoritative from his perspective, as distinguished from other writings that were not. This essay explores the process of canon formation in Nichiren Buddhism, focusing on the structure and argument of the Ris- sho ankoku ron. Noting five notions present in the process of canon forma tion, namely, selectivity, hierarchy, closure, orthodoxy, and legitimation, it examines the particular way these elements are manifest in the treatise in question.