“The doctrine of three thousand realms in one thought-moment (ichinen sanzen) first established by Great Master T’ien-t’ai [Chih-i] is the father and mother of the Buddhas,” Nichiren wrote. Quoting Chan-jan, he praised it as “the ultimate truth of his [Chih’i’s] teachings.” “It is clear that only the T’ien-t’ai [doctrine] of three thousand realms in one thought-moment is the path of attaining Buddhahood.” For Nichiren, the single thought-moment possessing three thousand realms was the heart of the Lotus Sūtra and the core of the Tendai teachings he had inherited. As Kanno Hiroshi has pointed out, it was by means of this doctrine that Nichiren sought to legitimize his own position within the T’ien t’ai/Tendai Buddhist tradition originating with Chih-i, and at the same time, also expressed the innovative aspects of his own teaching. (Page 263)