Ryōbu Shintō does not possess a closed, independent canon of scriptures that belong to it alone. Rather, it emerges as a way of reading and reconfiguring existing Buddhist and Shinto materials through a syncretic lens. Its doctrinal life unfolds in the interplay between esoteric Buddhist sutras, Shingon scholastic writings, and classical Shinto mytho-historical texts, all reinterpreted so that kami and buddhas mirror and illuminate one another. The “scriptures” of this tradition are therefore less a separate bookshelf and more a distinctive mode of commentary and correlation applied to already revered texts.

On the Buddhist side, the Mahāvairocana Sūtra (Dainichi-kyō) and the Vajraśekhara Sūtra (Kongōkai-kyō) stand at the center of this interpretive project. These esoteric scriptures, together with Shingon treatises attributed to Kūkai and his successors, provide the cosmological and ritual framework within which Ryōbu Shintō thinkers identify kami with buddhas and bodhisattvas. The doctrine of the “Two Realms” mandalas, drawn from these sources, becomes a key template for mapping the world of the kami onto the Womb and Diamond realms. In this way, the luminous figure of Mahāvairocana and the architecture of esoteric mandalas are made to resonate with the presence of deities such as Amaterasu.

On the Shinto side, texts like the Kojiki and Nihon Shoki, along with shrine records and ritual commentaries, are not discarded but reread. Genealogies of the kami, myths of creation, and liturgical formulas are subjected to Buddhist hermeneutics, so that purification rites, shrine lineages, and mythic episodes can be understood as expressions of deeper Buddhist principles. Works such as commentaries on purification rituals and shrine documents that incorporate Buddhist explanations of kami nature exemplify this tendency. They do not replace the older Shinto texts; they envelop them in a new web of meaning.

Finally, Ryōbu Shintō gives rise to synthetic doctrinal writings that explicitly work out the correspondences between kami and buddhas. These include honji suijaku treatises that articulate the relationship between “original ground” and “manifest traces,” as well as specialized expositions of the Ryōbu mandalas that align particular kami with specific deities of the Womb and Diamond realms. Such texts are best seen as bridges rather than foundations: they stand between Buddhist sutras and Shinto myths, weaving them into a single, if complex, tapestry of understanding. The heart of Ryōbu Shintō thus lies not in a unique scripture, but in a sustained practice of reinterpretation that allows two religious worlds to speak through one another.