Within Tendai, the text that stands at the heart of the entire tradition is the Lotus Sūtra (Saddharmapuṇḍarīka-sūtra, Myōhō Renge-kyō). It provides the doctrinal foundation for the vision of a single, all‑embracing vehicle to awakening and is treated as the lens through which other teachings are understood. Around this central scripture, Tendai gathers a wide range of Mahāyāna materials, but the Lotus Sūtra remains the touchstone against which other perspectives are harmonized and reinterpreted.

Alongside this primary sutra, the tradition accords near‑canonical authority to the great Tiantai treatises of Zhiyi, which function as both philosophical keys and practical manuals. The *Mohe zhiguan* (“Great Calming and Insight”) articulates a comprehensive meditative path, integrating calming and insight into a single, dynamic discipline. The *Fahua xuanyi* (“Profound Meaning of the Lotus Sūtra”) unfolds the deeper doctrinal structure of the Lotus, while the *Fahua wenju* (“Words and Phrases of the Lotus Sūtra”) offers a more detailed exegetical commentary. Together, these works provide the scaffolding through which the Lotus Sūtra’s vision is systematically expressed in thought and practice.

In the Japanese context, these Chinese foundations are further developed by key Tendai figures, whose writings adapt and extend the tradition. Saichō’s doctrinal works, for example, help establish a specifically Japanese articulation of Mahāyāna precepts and Lotus‑centered practice. Later Tendai masters such as Ennin, Enchin, Annen, and Genshin contribute scholastic and practical compendia that weave esoteric ritual and Pure Land devotion into the Lotus‑based framework, without displacing the primacy of the core texts. In this way, the living canon of Tendai is not a mere list of books, but a layered conversation centered on the Lotus Sūtra and illuminated by Zhiyi’s three great treatises.