The Trikaya doctrine (Sanskrit, literally "Three bodies or personalities"; 三身 Chinese: Sānshén, Japanese: sanjin) is an important Buddhist teaching both on the nature of reality, and what a Buddha is. By the 4th century CE the Trikaya Doctrine had assumed the form that we now know. Briefly the doctrine says that a Buddha has three 'bodies': the nirmanakaya or created body which manifests in time and space; the sambhogakaya or body of mutual enjoyment which is an archetypal manifestation; and the Dharmakaya or 'Reality body' which 'embodies' the very principle of enlightenment and knows no limits or boundaries.
The other thing that all Buddhas have in common, is the Dharma that they teach, which is identical in each case.
In the Pali Canon The Buddha tells Vasettha that the Tathagata (the Buddha) was Dharma-kaya, the 'Truth-body' or the 'Embodiment of Truth', as well as Dharmabhuta, 'Truth-become', that is, 'One who has become Truth' (Digha Nikaya). On another occasion, the Buddha told Vakkali:'He who sees the Dhamma (Truth) sees the Tathagata, he who sees the Tathagata sees the Dhamma (Samyutta Nikaya). That is to say, the Buddha is equal to Truth, and all Buddhas are one and the same, being no different from one another in the Dharma-kaya, because Truth is one.'
After the Buddha's Parinirvana a distinction was made between the Buddhas physical body, rupakaya; and his Dharmakaya aspect. This was an understandable and necessary development. As the Buddha told Vakkali, he was a living example of the 'Truth' of the Dharma. Without that form to relate to, the Buddha's followers could only relate to the Dharmakaya aspect of him. Despite the growth of the stupa cult in which the remains, or relics, of enlightened beings were worshipped, Buddhism sees such things as symbols of the Truth, rather than the Truth itself.
The Sambhogakaya is that aspect of the Buddha, or the Dharma, that one meets in visions and in deep meditation. It could be considered an interface with the Dharmakaya. What it does, and what the Tathagatagarbha doctrine also does, is bring the transcendental within reach, it makes it immanent.
Buddhist philosophical concepts | Buddhist terms
Trikaya | سه کالبد بودا | Nirmāṇakāya | 三身 | Trzy ciała Buddy | Три тела Будды | Tam thân