Tendai

Tendai (天台宗, Tendai-shū^?) is a Japanese school of Mahayana Buddhism, a descendant of the Chinese Tiantai or Lotus Sutra school.

David W. Chappell frames the relevance of Tendai for a universal Buddhism:

Although Tendai (Chin., T'ien-t'ai) has the reputation of being a major denomination in Japanese history, and the most comprehensive and diversified school of Chinese Buddhism, it is almost unknown in the West. This meagre presence is in marked contrast to the vision of the founder of the movement in China, T'ien-t'ai Chih-i (538-597), who provided a religious framework which seemed suited to adapt to other cultures, to evolve new practices, and to universalize Buddhism.

The Tiantai was founded by Zhiyi and its teaching was first brought to Japan by the Chinese monk Ganjin (鑑眞) in the middle of the 8th century, in what became the short-lived Ritsu school, but it was not widely accepted. In 805, the Japanese monk Saichō (最澄; also called Dengyō Daishi 伝教大師) returned from China with new Tiantai texts and made the temple that he had built on Mount Hiei (比叡山), Enryaku-ji (延暦寺), a center for the study and practice of what became Japanese Tendai.

Philosophically, the Tendai school did not deviate substantially from the beliefs that had been created by the Tiantai school in China. However, what Saichō transmitted from China was not exclusively Tiantai, but also included Zen (禅, trad. 禪), the esoteric Mikkyō (密教), and Vinaya School (戒律) elements. The tendency to include a range of teachings became more marked in the doctrines of Saichō's successors, such as Ennin (圓仁) and Enchin (圓珍). However, in later years, this range of teachings began to form sub-schools within Tendai Buddhism. By the time of Ryōgen, there were two distinct groups on Mt. Hiei: the Sammon "Mountain Group" (山門派) who followed Ennin and the Jimon "Temple Group" (寺門派) who followed Enchin.

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Wikipedia