Within Shingon, mantra recitation is regarded as a central esoteric discipline because it is understood to be the very “true word” of the Buddha rather than a mere symbol or devotional formula. Mantras are treated as the actual sound-form or speech-body of Dainichi Nyorai, the cosmic Buddha, and thus as direct expressions of enlightened consciousness. To voice a mantra is therefore to participate in the Buddha’s own speech, not simply to speak about the Buddha. In this perspective, the transformative power of mantra lies less in conceptual meaning and more in sound, rhythm, and proper ritual context, received and practiced within an authentic lineage.

This practice is framed within the Shingon teaching of the “Three Mysteries” (sanmitsu): body, speech, and mind. Mantra corresponds to the mystery of speech and is performed together with mudrā (hand seals) and visualization of mandalas or deities. Through this coordinated discipline, the practitioner’s body, speech, and mind are gradually aligned with those of the Buddha, advancing toward the realization of Buddhahood in this very body. Mantra recitation thus becomes a concrete method for transforming ordinary speech into Buddha’s speech and for revealing the Buddha-nature that is already present.

Ritually, mantras structure and empower Shingon ceremonies, consecrations, and other esoteric rites. They are used to establish sacred space, to “call forth” and affirm the presence of Buddhas and bodhisattvas, and to make offerings spiritually effective. In this way, mantra recitation integrates practitioner, altar, deities, and cosmos into a single esoteric field, where spiritual power is invoked for protection, purification, and awakening. The practice is understood not only as a means of inner transformation but also as a way of participating in the living transmission that flows from Dainichi Nyorai through the lineage of Shingon masters.