Zhiyi worked the threefold truth out most fully in the Mohe Zhiguan, his manual of calming and contemplation delivered as lectures and later written down by his disciple Guanding. There the doctrine produces its most famous corollary, that the three thousand realms of existence, every possible state of being multiplied across every possible world, are present whole in a single moment of ordinary thought. The number itself is built from the school's own arithmetic of worlds and states rather than chosen for effect, but the claim it serves is the same one carried by the three truths themselves, that emptiness, provisional existence and the middle are not stages a practitioner passes through toward something better but three descriptions of exactly what is already present in this moment, none of them more final than the others. Meditation practice follows from the claim rather than illustrating it. If the whole of reality is already contained in one moment of mind, then contemplating that single moment with sufficient attention is not a shortcut to something greater, it is the practice itself, complete. Saicho carried the formulation to Mount Hiei and it remained Tendai's doctrinal spine through the medieval centuries in which Honen, Shinran, Dogen and Nichiren all trained there before each left to found a narrower school of his own around one piece of what Tiantai had held together.