Saichō’s establishment of the Tendai school in Japan unfolded as a careful weaving together of pilgrimage, doctrine, and institution. After traveling to China as part of an official mission, he studied Tiantai Buddhism at Mount Tiantai and received formal transmission of its teachings, texts, and ritual practices, including esoteric elements. Returning to Japan with essential Tiantai scriptures, commentaries, and esoteric manuals, he possessed both the doctrinal foundation and ritual resources needed to plant this tradition in new soil. This transmission was not merely textual; it carried a vision centered on the Lotus Sūtra and the Tiantai understanding of the “One Vehicle,” in which all beings are seen as capable of Buddhahood.

On Mount Hiei, near the new capital, Saichō transformed his existing monastery, Enryaku-ji, into the institutional heart of this emerging school. With imperial patronage, especially as an alternative to the older Nara establishments, Enryaku-ji gained recognition and authority as the headquarters of Japanese Tendai. From this mountain base, he promoted a comprehensive curriculum that integrated Tiantai doctrine, meditation, esoteric ritual, and other Mahāyāna elements, all harmonized under the primacy of the Lotus Sūtra. The result was not a narrow sectarian enclave, but a broad, synthesizing tradition that functioned almost like a Buddhist university.

A crucial dimension of Saichō’s work lay in reshaping ordination and training. He challenged the dominance of the Nara ordination system and petitioned for an independent Mahāyāna ordination platform on Mount Hiei, grounded in bodhisattva precepts rather than the older framework alone. Although this platform was fully authorized only after his death, the effort itself marked a decisive step toward institutional independence. Alongside this, he instituted a rigorous twelve-year training program for monks on Mount Hiei, emphasizing disciplined practice, doctrinal study, and a life of seclusion and commitment.

Through these interlocking moves—receiving and transmitting Tiantai teachings, founding and elevating Enryaku-ji, securing imperial recognition, integrating esoteric practices, and establishing a distinct ordination and training system—Saichō gave Tendai in Japan both spiritual depth and institutional solidity. The school that emerged from his vision became a powerful, all-encompassing matrix of Mahāyāna thought and practice, from which many later currents of Japanese Buddhism would eventually flow.