Within Ryōbu Shintō, Buddhism functions as the dominant doctrinal and interpretive matrix into which the indigenous kami tradition is woven. Buddhist cosmology, teachings on karma and rebirth, and the path to enlightenment provide the primary theological framework, while Shinto offers the local deities and sacred sites through which these principles are expressed. The Buddhist notion of honji suijaku, the relationship of “original ground” and “manifest traces,” becomes a key hermeneutic: kami are understood as localized manifestations or emanations of buddhas and bodhisattvas, rather than independent, unrelated beings. In this way, the universal and the local are bound together, with Buddhist divinities supplying the ultimate ground and the kami serving as their accessible, this-worldly appearances.

This integration is especially shaped by esoteric Buddhism, which supplies a rich symbolic and ritual vocabulary. The two great mandalas of esoteric thought, often associated with Womb and Diamond realms, are used to map and correlate Buddhist deities and kami, so that the sacred landscape of Japan is read through a mandalic vision. Buddhist mantras, mudrās, and liturgical forms are taken up in shrine contexts, and ceremonies at syncretic sites follow patterns derived from temple ritual. Meditation techniques and scriptural recitation also enter into the life of these shrines, so that devotion to kami unfolds within recognizably Buddhist modes of practice.

On the institutional and practical level, Buddhist monks frequently oversee such syncretic shrines and conduct their major ceremonies, further reinforcing the primacy of Buddhist structures. Buddhist sutras and commentaries serve as authoritative texts that articulate the meaning of kami worship, granting it a place within a broader soteriological horizon aimed at enlightenment. Thus, the kami are not only guardians of place or bestowers of worldly benefits, but are interpreted as agents participating in the Buddhist path to liberation. Through this layered synthesis, Buddhism provides Ryōbu Shintō with its overarching metaphysical vision, ritual order, and salvific orientation, while Shinto grounds that vision in the concrete presence of Japan’s indigenous deities.