Nichiren took the ichinen sanzen concept that Zhiyi had briefly delineated and made it the foundation of his teaching. For Nichiren, ichinen sanzen was “the father and mother of the buddhas.” He often referred to it in its “short form,” so to speak, as the mutual inclusion of the ten dharma realms… . Because the “ten suchnesses” (referred to at the beginning of the “Skillful Means” chapter) and the mutual inclusion of the ten realms are both concepts integral to the single thought-moment that is three thousand realms, the one implied the other, and Nichiren could take “the real aspect of all dharmas” or the ten suchnesses as pointing to the mutual inclusion of the ten realms. For him, this teaching was unique to the Lotus Sūtra and was what qualified it as the “wonderful dharma.” In one passage, he writes: “The sūtras that the Buddha preached for more than forty years before the Lotus do not set forth the mutual inclusion of the ten realms. And because they do not set forth the mutual inclusion of the ten realms, one cannot know the buddha realm within one’s own mind, and because one does not know the buddha realm within one’s own mind, the buddhas do not manifest externally either. … But now with the Lotus Sūtra, the buddha realm within the nine realms was opened, and those who had heard the Buddha’s forty and more years of preaching — bodhisattvas, persons of the two vehicles, and ordinary beings of the six paths — could for the first time see the buddha realm within themselves.”