Tiantai, named after the mountain where Zhiyi taught in the sixth century, classified all Buddhist teachings with the Lotus Sūtra at the summit. It taught the threefold truth of emptiness, conventional existence and the middle, and the idea that three thousand worlds are present in a single moment of thought. In Japan it became Tendai.
Tiantai
The Chinese school founded by Zhiyi on the Lotus Sūtra, teaching the threefold truth and calm-and-insight meditation.
Also: Tendai