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 kayas or bodies: the nirmanakaya or created body which manifests in time and space; the sambhogakaya or body of mutual enjoyment which is a body of bliss or clear light manifestation; and the Dharmakaya or Truth body which embodies the very principle of enlightenment and knows no limits or boundaries. In the view of Anuyoga, the 'Mindstream' (Sanksrit: citta santana) is the 'continuity' (Sanskrit: santana; Wylie: rgyud) that links the Trikaya. The Trikaya, as a triune, is symbolised by the Gankyil.
Buddhism has always recognized more than one Buddha. In the Pali Canon twenty-eight previous Buddhas are mentioned, and Gautama Buddha, the historical Buddha, is simply the Buddha who has appeared in our world age. Even before the Buddha's Parinirvana the term Dharmakaya was current. Dharmakaya literally means Truth body, or Reality body. However all of these Buddha are unified in two ways: firstly they share similar special characteristics. All Buddhas have the 32 major marks, and the 80 minor marks of a superior being. These marks are not necessarily physical, but are talked about as bodily features. They include the 'ushinisha' or a bump on the top of the head; hair tightly curled; a white tuft of hair between the eyes, long arms that reach to their knees, long fingers and toes that are webbed; his penis is completely covered by his foreskin; images of an eight-spoked wheel on the soles of their feet etc.
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 Dharmakaya, the 'Truth-body' or the 'Embodiment of Truth', as well as Dharmabhuta, 'Truth-become', that is, 'One who has become Truth' (Digha Nikaya 27.9).
On another occasion, Ven. Vakkali, who was ill, wanted to see the Buddha before he died from old age. The text from the Samyutta Nikaya (SN 22.87) is as follows:
...and the Buddha comforts him, "Enough, Vakkali. Why do you want to see this filthy body? Whoever sees the Dhamma sees me; whoever sees me sees the Dhamma."
Similarly in this same text, the term Putikaya meaning "decomposing" body is distinguished from the eternal Dhamma body of the Buddha and of course the Bodhisattva body.
Trikaya and Mahayana
Later Mahayana Buddhists were concerned with the transcendent aspect of the Dharma. One response to this was the development of the Tathagatagarbha Doctrine. Another was the introduction of the Sambhogakaya, which conceptually fits between the Rupakaya, now renamed Nirmanakaya and the Dharmakaya.
- The Nirmaṇakāya is a physical body of a Buddha. An example would be Gautama Buddha's body.
- The Sambhogakāya is the reward-body, whereby a bodhisattva completes his vows and becomes a Buddha. Amitabha, Vajrasattva and Manjushri are examples of Buddhas with the Sambhogakaya body.
- The Dharmakāya is the embodiment of the truth itself, and it is commonly seen as transcending the forms of physical and spiritual bodies. Vairocana Buddha is often depicted as the incomprehensible Dharmakaya, particularly in esoteric Buddhist schools such as Shingon and Kegon in Japan.
As with earlier Buddhist thought, all three forms of the Buddha teach the same Dharma, but take on different forms to expound the truth.
The Three Bodies of the Buddha from the point of view of Zen Buddhist thought are not to be taken as absolute, literal, or materialistic; they are expedient means that "are merely names or props" and only the play of light and shadow of the mind. 
"Do you wish to be not different from the Buddhas and patriarchs? Then just do not look for anything outside. The pure light of your own heart [i.e., 心, mind] at this instant is the Dharmakaya Buddha in your own house. The non-differentiating light of your heart at this instant is the Sambhogakaya Buddha in your own house. The non-discriminating light of your own heart at this instant is the Nirmanakaya Buddha in your own house. This trinity of the Buddha's body is none other than he here before your eyes, listening to my expounding the Dharma."
Dakinis can also be classified according to the Trikaya, or three bodies of a Buddha. The dharmakaya dakini, which is Samantabhadri, represents the dharmadhatu where all phenomena appear. The sambhogakaya dakinis are the yidams used as meditational deities for tantric practice. The nirmanakaya dakinis are human women born with special potentialities, these are realized yogini, the consorts of the gurus, or even all women in general as they may be classified into the five Buddha-families.
The Svabhavikakaya is simply the unity or non-separateness of the three kayas. 
The term Svabhavikakaya is also known in Gelug teaching, where it is one of the assumed two aspects of dharmakaya: Essence Body/Svabhavikakaya and Wisdom Body or Body of Gnosis/Jnanakaya. .
- ↑ 1.0 1.1 Welwood, John (2000). The Play of the Mind: Form, Emptiness, and Beyond. Source: http://www.purifymind.com/PlayMind.htm (accessed: Saturday January 13, 2007)
- ↑ http://www.accesstoinsight.org/tipitaka/dn/dn.16.5-6.than.html See footnote #3
- ↑ Hattori, Sho-on (2001). A Raft from the Other Shore : Honen and the Way of Pure Land Buddhism. Jodo Shu Press. pp. 25–27. ISBN 4883633292.
- ↑ Schloegl, Irmgard (1976). The Zen Teaching of Rinzai. Shambhala Publications, Inc.. p. 21. ISBN 0-87773-087-3.
- ↑ Cf. Capriles, Elías (2003/2007). Buddhism and Dzogchen'', and Capriles, Elías (2006/2007). Beyond Being, Beyond Mind, Beyond History, vol. I, Beyond Being
- ↑ remarks on Svabhavikakaya by khandro.net
- ↑ explanation of meaning
- ↑ In the book Embodiment of Buddhahood Chapter 4 the subject is: Embodiment of Buddhahood in its Own Realization: Yogacara Svabhavikakaya as Projection of Praxis and Gnoseology.
- ↑ khandro.net citing H.E. Tai Situpa
- ↑ Paul Williams: Mahayana Buddhism: The Doctrinal Foundations (Library of Religious Beliefs & Practices),Routledge, ISBN 0415025370 (10), ISBN 978-0415025379 (13),
- ↑ see Makransky, page 115
- Snellgrove, David (1987). Indo-Tibetan Buddhism, Vol. 1. Boston, Massachusetts: Shambhala Publications, Inc.. ISBN 0 87773 311 2.
- Snellgrove, David (1987). Indo-Tibetan Buddhism, Vol. 2. Boston, Massachusetts: Shambhala Publications, Inc.. ISBN 0 87773 379 1.
- John J. Makransky: (August 1997) Buddhahood Embodied: Sources of Controversy in India and Tibet, Publisher: State University of New York Press , ISBN 079143432X (10), ISBN 978-0791434321 (13), 
- Trikaya del Lama Kunsal Kassapa
- trikāya - A Dictionary of Buddhism
- Khandro: The Three Kayas
- Kagyu: The Three Kayas
- 32 marks of the Buddha ("THIRTY TWO MARKS OF A GREAT MAN")