|The Trikāya Buddha, Shanyuan Temple, Liaoning Province, China.|
Trikaya (Tib. Skugsum) . lit. 3 bodies, or threefold embodiment. (1.) Three representations of Buddha, viz. his statue, his teachings, and his stupa (q. v.) (2.) The historical Buddha, as uniting in himself 3 bodily qualities, see Dharmakaya, Sambhogakaya and Nirmanakaya. (3.) Buddha, as having passed through, and still existing in, 3 forms or persons, viz. (a) as " Sakyamuni (or earthly Buddha, endowed with the Nirmanakdya which passed through 100,000 kotis of transformations " (on earth) ; (b.) as " Lochana (or heavenly Dhyani Bodhisattva, endowed with the) Sambhogakaya of absolute completeness " (in Dhyana); (c.) as "Vairochana (or Dhyani Buddha, endowed with the Dharmakaya of absolute purity " (in Nirvana). In speaking of Buddha as now combining the foregoing (historically arranged) persons or forms of existence, the order here given is, of course, reversed. As to how this doctrine arose, we can only guess. Primitive Buddhism in China distinguished a material, visible and perishable body (rupa kaya) and an immaterial, invisible and immortal body, dharma kaya, as attributes of human existence. This dichotomy— probably taught by Sakyamuni himself—was even afterwards retained in characterizing the nature of ordinary human beings. But in later ages, when the combined influence of Shivaism, which ascribed to Shiva a threefold body (Dharmakaya, Sarmbhogakaya and Nirmanakaya) and Brahminism, with its Trimurti (of Brahma, Vishnu and Shiva) gave rise to the Buddhist dogma of a Triratna (Buddha, Dharma and Sahgha), trichotomism was taught with regard to the nature of all Buddhas.
Bodlhi being the characteristic of a Buddha, a distinction was now made of " essential Bodhi " as the attribute of the Dharmakaya, " reflected Bodhi '' as the attribute of the Sambhogakaya, and " practical Bodhi" as the attribute of the Nirmanakaya; and Buddha, combining in himself these 3 conditions of existence, was said to be living, at the same time, in 3 different spheres, viz. (1.) as " having essentially entered Nirvana," being as such a Dhyani Buddha, living in Arupadhatu in the Dharmakaya state of essential Bodhi, (2.) as " living in reflex in Rupa dhatu " and being, as such, in the intermediate degree of a Dhyani Bodhisattva in the Sambhogakaya state of reflected Bodhi, and (3.) as "living practically in Kamadhatu," in the elementary degree of a Manuchi Buddha in the Nirmanakaya state of practical Bodhi. In each of these 3 forms of existence, Buddha has a peculiar mode of existence, viz., (1.) absolute purity as Dhyani Buddha, (2.) absolute completeness as Dhyani Bodhisattva, and (3.) numberless transformations as Manuchi Buddha. Likewise also Buddha's influence has a different sphere in each of these 3 forms of existence, viz., (1.) as Dhyani Buddha he rules in the "domain of the spiritual " (4th Buddha kchetra), (2.) as Dhyani Bodhisattva he rules in the "domain of success " (3rd Buddha kchetra), and (3.) as "Manuchi Buddha he rules in the domain of mixed qualities " (1st and 2nd Buddhakchetra). There is clearly the idea of a unity in trinity underlying these distinctions and thus the dogmas of the Trailokya, Trikaya' and the Triratna (q. T.) are interlinked, as the subjoined synoptic table shows in detail (Eitel, Ernest J. Handbook of Buddhism, Hong Kong, 1888).
The Trikaya doctrine of Buddhism, i.e., the doctrine that the Buddha has three "bodies," is notorious for its complexities. Attributed to the Yogacara, but regarded as typical of the Mahayana in general, it is customarily cited in books on Buddhism in terms of the triad dharma-kaya, sambhoga-kaya (or sambhogika-kaya) and nirmana-kaya (or nairmanika-kaya). Taking these in ascending order of abstraction, the nirmana-kaya, usually translated "apparitional body," "phantom body," "transformation body," etc., is the physical manifestation of Buddhahood, the ordinary perishable human form, as exemplified by the "historical Buddha," Siddhartha Gautama. The sambhoga-kaya ("body of bliss," "reward body," "enjoyment body," etc.) is a more exalted and splendid manifestation of the enlightened personality, still in the realm of form, but visible only to bodhisattvas, those of advanced spiritual capabilities. By contrast, the dharma-kaya ("Dianna-body," "Body of Truth," "Cosmic Body," "Absolute Body," etc.) is both formless and imperishable, representing the identification of the Buddha with the truth which he revealed, or with reality itself. As such the dharma-kaya is often linked with various terms for reality, such as dharmata, dharma-dhatu, and so on, and has even been regarded as a kind of Buddhist absolute, or at least at one with it. In this light the dharma-kaya is understood as the primal "source" or "ground" from which the other two types of bodies emanate. While many scholars are content to describe this in purely abstract terms, others impute personal characteristics to it; and at least one writer has gone so far as to compare it to the Christian idea of Godhead. (Harrison, Paul (1992). Is the Dharma-Kāya the Real "Phantom Body" of the Buddha?. Journal of the International Association of Buddhist Studies 15 (1), 44)