For entering the heart of Tiantai thought, the three great works of Zhiyi stand as the indispensable gateway. The *Fahua Xuanyi* (“Profound Meaning of the Lotus Sutra”), the *Fahua Wenju* (“Words and Phrases of the Lotus Sutra”), and the *Mohe Zhiguan* (“Great Calming and Contemplation”) together articulate both the doctrinal architecture and the contemplative praxis that define this tradition. These texts do not merely comment on scripture; they weave scriptural exegesis, philosophical reflection, and meditative guidance into a single, integrated vision. Through them, Tiantai’s characteristic concern with the classification of teachings, the harmonization of diverse doctrines, and the union of calming and insight becomes transparent.

At the scriptural center of this edifice stands the *Lotus Sutra* itself, regarded as the pivotal revelation around which Tiantai interpretation turns. Zhiyi’s two commentaries, the *Fahua Xuanyi* and *Fahua Wenju*, may be seen as twin lenses through which the sutra’s deeper meaning and its precise wording are brought into focus. Alongside the Lotus, other scriptures such as the *Nirvana Sutra*, the *Avatamsaka Sutra*, and the *Vimalakirti Sutra* are repeatedly drawn upon to illuminate themes like Buddha‑nature, the vast interpenetration of phenomena, and non‑dual wisdom. In this way, Tiantai does not isolate the Lotus Sutra but situates it within a broad scriptural tapestry.

Later Tiantai masters extend and refine this foundation rather than replace it. The writings of figures such as Zhanran, especially his commentarial work on Zhiyi’s three major treatises, serve to clarify, defend, and systematize the earlier tradition. Subsequent exponents like Zhili continue this line of interpretation, ensuring that the core insights of Zhiyi’s synthesis remain a living current rather than a static doctrine. For a serious student, however, these later works are best approached as echoes and elaborations of the primary quartet: the *Lotus Sutra* and Zhiyi’s three great treatises, which together form the essential corpus for understanding Tiantai’s integration of all Buddhist teachings under the banner of the Lotus.