Dharmadhatu

Dharmadhatu (Sanskrit) is the 'dimension', 'realm' or 'sphere' (dhātu) of the Dharma or Absolute Reality.

In Mahayana Buddhism, dharmadhātu (Standard Tibetan: chos kyi dbyings; Chinese: 法界) means "realm of phenomena", "realm of Truth", and of the noumenon. It is referred to by several synonymous terms from Mahayana Buddhist philosophy, such as Tathata (Reality "as-it-is"), emptiness, dependent co-arising and eternal Buddha. It is the "deepest nature, or essence".

Dharmadhātu is the purified mind in its natural state, free of obscurations. It is the essence-quality or nature of mind, the fundamental ground of consciousness of the trikaya, which is accessed via the mindstream.

When the buddha-nature has been realised, dharmadhātu is also referred to as the Dharmakāya, the Body of Dharma Truth.

It is associated with Vairocana.

Kang-nam Oh traces the origin of dharmadhatu to the Avatamsaka Sutra. It has been further developed by the Hua-yen school:

This idea of dharmadhātu-pratītyasamutpāda which was originally found in the Avataṁsaka-sūtra or Hua-yen ching, was fully developed by the Hua-yen school into a systematic doctrine palatable to the Chinese intellectual taste. The dharmadhātu doctrine can be said to have been, by and large, set forth by Tu-shun (557~640 C.E.), formulated by Chih-yen (602~668), systematized by Fa-tsang (643~712), and elucidated by Ch’eng-kuan (ca. 737~838) and Tsung-mi (780~841).

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