The Trikāya (Sanskrit: त्रिकाय, lit. "three bodies"; Chinese: 三身; pinyin: sānshēn; Japanese pronunciation: sanjin, sanshin; Korean pronunciation: samsin; Vietnamese: tam thân, Tibetan: སྐུ་གསུམ, Wylie: sku gsum) is a fundamental Mahayana Buddhist doctrine that explains the multidimensional nature of Buddhahood. As such, the Trikāya is the basic theory of Mahayana Buddhist Buddhology (i.e. the theology of Buddhahood).[1]
This concept posits that a Buddha has three distinct "bodies", aspects, or ways of being, each representing a different facet or embodiment of Buddhahood and ultimate reality.[2] The three are the Dharmakāya (Sanskrit; Dharma body, the ultimate reality, the Buddha nature of all things), the Sambhogakāya (the body of self-enjoyment, a blissful divine body with infinite forms and powers) and the Nirmāṇakāya (manifestation body, the body which appears in the everyday world and presents the semblance of a human body). It is widely accepted in Mahayana that these three bodies are not separate realities, but functions, modes or "fluctuations" (Sanskrit: vṛṭṭis) of a single state of Buddhahood.
The Trikāya doctrine explains how a Buddha can simultaneously exist in multiple realms and embody a spectrum of qualities and forms, while also seeming to appear in the world with a human body that gets old and dies (though this is merely an appearance). It is also used to explain the Mahayana doctrine of non-abiding nirvana (apratiṣṭhita-nirvana), which sees Buddhahood as both unconstructed (asaṃskṛta) and transcendent, as well as constructed, immanent and active in the world.[3] This idea was developed in early Yogācāra school sources, like the Mahāyāna-sūtrālamkāra. The doctrine's interpretations vary across different Buddhist traditions, some theories contain extra "bodies", making it a "four body" theory and so on. However, the basic Trikāya theory remains a cornerstone of Mahayana and Vajrayana teachings, providing a comprehensive perspective on the nature of Buddhahood, Buddhist deities and the Buddhist cosmos.[4] The Buddhist triple body theory was also adopted into Daoist philosophy and modified using Daoist concepts.