The T'ien-t'ai School is a Chinese innovation, and one of the two main philosophical schools of Chinese Buddhism, the other being the Hua-yen. As it is based on the Lotus Sutra (Skt. Saddharmapundarika Sutra; Ch. Fa-hua ching) it is also called the Fa-hua, or Lotus, School. T'ien-t'ai doctrine contains three elements: a classification system for Buddhist texts and teachings; metaphysics; and teaching on meditation.
The T'ien-t'ai classification system is a solution to the problem of how to reconcile the different doctrines found in separate texts. It divides texts and doctrines into "five periods and eight teachings". The five periods correspond to five the consecutive periods which the T'ien-t'ai claim made up the Buddha’s ministry. In the first period, lasting three weeks, and immediately after his enlightenment, the Buddha is said to have taught the Avatamsaka Sutra or Flower Garland Scripture, the text of the Hua-yen School. Unfortunately only the most advanced Bodhisattvas could understand its profundities, so in the next period, lasting twelve years, he taught the much more simple teachings of the Agamas or Nikayas of Hinayana (Theravada) Buddhism. In the third, eight year, period, he is said to have taught various scriptures containing the elementary doctrines of Mahayana Buddhism, and in the fourth period, lasting twenty-two years, the Buddha gave the advanced Mahayana doctrine of emptiness in the form of the Prajnaparamita Sutras. Finally in the fifth period, lasting eight years, he taught again the absolute truth of Buddhism, this time in the Lotus Sutra, and, just before his death and entry into Nirvana, in the Mahaparinirvana Sutra.
The classification into "eight teachings" cannot be explained in detail here. Very briefly, four of the eight categories are of levels of doctrine, largely corresponding to those implied in the five periods (if the first and last periods are counted as one in terms of their doctrinal content). The remaining four categories are to do with the method in which the Buddha taught the doctrine
In the above way the T'ien-t'ai found a place for all Buddhist texts and teachings. Each was seen as correct and appropriate at a certain time and for a certain person, and part of the Buddha’s skill-in-means (Skt. upaya) was in knowing precisely which doctrine to teach in any given situation.
The T'ien-t'ai accepted the basic doctrines of the San-lun and Fa-hsiang Schools, but reinterpreted them in a way which, by allowing more importance to be attached to the phenomenal world, was more compatible with the Chinese world view. Phenomena were understood to be "empty" of any independent nature as the San-lun claimed, but they nonetheless did have temporary existence. The ultimate truth of the nature of phenomena, and the ultimate truth itself, was the combination and reconciliation of these two truths. Thus phenomena themselves, the everyday objects of the physical world, were all embodiments of the ultimate or "middle" truth: as the T'ien-t'ai saying states, “Every colour of fragrance is the Middle Way”. Similarly, although the world was a creation of the One Mind as the Fa-hsiang School maintained, it was not to be transcended as an illusion. Rather it was ultimately to be accepted as an eternal and integral part of the One Mind, which was also the Dharma-kaya, or body of the cosmic Buddha. Thus all things are harmoniously and inseparably one in the universal One Mind/Buddha-nature, a doctrine summarised in the T'ien-t'ai aphorism, “One thought is the three thousand worlds”.
The T'ien-t'ai understanding of the two basic forms of Buddhist meditation, samatha or "cessation" (Ch. chih) and vipasyana or "contemplation" (Ch. kuan), reflected the School’s metaphysics. Cessation meditation gives knowledge of emptiness and Nirvana, but this is complemented and balanced by contemplation meditation, which reveals that emptiness and Nirvana are not separate or different from the phenomenal world.
The T'ien-t'ai School was founded by the brilliant monk Chih-i (538-597), although the School recognises two patriarchs before him, the monks Hui-wen (flourished 550) and Hui-ssu (515-577), Chih-i’s teacher.
Chih-i started to teach in his early twenties, and in 575 settled on Mount T'ien-t'ai, after which the School is named. He expounded his interpretation of the Lotus Sutra (translated in 406) and other scriptures, and at the same time he worked on his comprehensive classification system of Buddhist texts and teachings. Such systems had begun to appear in northern China at least a century and a half previously, as attempts to order and reconcile the numerous and varied texts being translated. Chih-i drew on these earlier efforts in developing his own system, which was so scholarly, comprehensive, and sophisticated, that it was widely accepted, few being sufficiently competent to argue with Chih-i’s erudition.
Chih-i’s fame as a master of Buddhist doctrine reached the emperor of the Ch’en Dynasty (557-589) who invited him to lecture at the capital Chin-ling, and gave the monastery at Mount T'ien-t'ai official and financial support. When the Chen Dynasty was replaced by the Sui Dynasty in 589, Chih-i established an equally positive relationship with the new rulers. With the combination of state patronage and the capable leadership of Chih-i, the T'ien-t'ai School flourished. Chih-i is recorded as being responsible for the construction of thirty-five monasteries, and the ordination of more than a thousand monks. The T'ien-t'ai also absorbed one of the scholastic study groups, the Nieh-p’an based on the Mahaparinirvana Sutra, a text which the T'ien-t'ai rated alongside the Lotus Sutra in its classification system.
In 618 rebels usurped the Sui throne and founded the T’ang Dynasty. The T’ang rulers wished to distance themselves from the policies and affiliations of their dynastic predecessors, and thus imperial support was transferred away from the T'ien-t'ai, first to the Fa-hsiang School, and then to the Hua-yen School. The T'ien-t'ai fell into decline, although the School’s ninth patriarch, Chan-jan (711-782), did have some success in re-propagating its teachings. The School survived the persecution of 845, but it was greatly weakened, many of its texts having being destroyed. Today T'ien-t'ai teachings survive as a doctrinal tradition within the Ch’an School, where they continue to be studied.
The harmonious and integrative doctrines of the T'ien-t'ai were well-suited to the Chinese temperament, and there is no doubt that but for the vagaries of dynastic history the School’s material success would have been more prolonged. Its doctrinal influence on Chinese Buddhism has been profound nonetheless, and is exceeded only by that of the Hua-yen School.