 Kūkai in several works (especially in Shōjijissōgi and Unjigi) explicates the syllabic letter A as signifying the above-mentioned “primal non-originating” character of all thing-events, as the “mother” of all syllables, letters, and languages, and the king of all mantras. The sound A is also the primal sound made when the mouth first opens to exhale. And in its written form, A constitutes the first stroke of every other syllable. A is the first syllable of the Sanskrit alphabet as well as of the Sanskrit words for “origin” (ādi) and “unborn” (anutpāda), combined in the Sanskrit word “primal non-origination” (ādyanutpāda). It is also the first letter of the root mantra of Dainichi as depicted in the Taizō Mandara (which we shall discuss below): A Vi Ra Hūṃ Kham (Jpn: A Bira Un Ken). Furthermore in Sanskrit, A is used as a negative prefix. All of these manifold meanings are combined in Shingon’s mantric use of A to represent the primal vocalization of Dainichi. Its omnipresence in form and sound symbolizes the Buddha-nature of the hosshin pervading everywhere, while condensing the significance of that all-prevalence within its singular form and sound. But its all-pervasiveness also means the origin of all things in their interdependence, that is, their interdependent origination, hence emptiness. This emptiness of substance is denoted by its use as a negative prefix, i.e., the absence of self-presence in infinite referentiality. As stated above, A signifies the “primal non-originating” character of all being. For in signifying the origin of all in their on-going dependent origination A is thus the “origin of no origin.” What this points to is the endlessness of the chain of conditions behind each thing-event, never reaching an ultimate origin or first cause. But paradoxically this primal absence of any distinguishing origin, this ubiquitous in-difference of all differentiation, is itself the ultimate origin of all thing-events in their mutual differentiations and co-relativity. Or put differently, Dainichi’s mind (along with his body), making no discrimination between this and that, is like a great space (“emptiness”; kū) from out of which he transforms himself through self-differentiation into the myriad thing-events and beings. This causeless cause is symbolized in the last letter in Sanskrit, the letter H, the first letter of the mantra Hūṃ (Jpn: Un). Its meaning thus coincides with the “primal non-origination” denoted by the first letter of the alphabet, A. The syllable A, together with H then embodies the meanings of emptiness, dependent origination, and primal non-origination, all expressing the beginningless and endless dynamic non-substantiality of the entire cosmos and all being, the empty space that is the body of the hosshin, the Dharma of all dharmas.