Tiantai zong; one of the thirteen schools of Buddhism in China 十三宗， and Japan. Also called the "Lotus Sutra School" 法华宗.
（1） China: A Maha^ya^na school established by Zhiyi 智顗 of Tiantai mountain. Zhiyi， taking the Lotus Sutra 法华经 as his basis， classified the other Buddhist sutras into five periods 五时 and eight types of teachings; he discussed the theory of perfect interpenetration of the triple truth 三谛 and taught the rapid attainment of Buddhahood through the practice of observing the mind. The Chinese line of transmission starts with Huiwen 慧文 of the Northern Chi and follows with Huisi 慧思. Next Zhiyi explained the three great scriptures of the school 法华三部 emphasizing both scriptural study and practice. The sixth patriarch， Jingqi 荆溪 also popularized the sect through his commentaries on these three scriptures.
（2） Korea: Tiantai was introduced to Korea as Ch'ont'ae a couple of times during earlier periods， but was not firmly established until the time of Uich'on 义天 （1055-1101） who established Ch'ont'ae in the Koryo as an independent sect. Due to Uich'on's influence， it came to be a major force in the world of Koryo Buddhism. After he returned from Song China in 1086， Uich'on sought to ease conflict between the doctrinal 教 schools and Son 禅 schools， believing that the Ch'ont'ae doctrine would be effective to this end. Ch'ont'ae would eventually die out in Korea， its teachings being absorbed into the Chogye Son 曹溪tradition.
（3） Japan: The Tiantai teaching was brought to Japan by Jianshen 鑒真 in the middle of the 8th century， but it was not widely accepted. In 805， Saicho^ 最澄 brought back the Tendai teachings from China and made the temple that he had built on Mt. Hiei 比睿山， the Enryakuji， a center for the study and practice of Tendai. However， what he had transmitted from China was not exclusively Tendai， but also included Zen 禅， Esoteric 密教 and Monastic Discipline 戒律 teachings. This tendency became more marked in the doctrines of his successors， such as Ennin 圆仁 and Enchin 圆珍. The Tendai sect flourished under the patronage of the imperial family and nobility in Japan.