To say that “the nine realms possess the Buddha realm” is a statement about ontology; it does not mean that deluded persons experience or perceive the world as Buddhas do, or that they act as Buddhas act. To transform consciousness, practice is necessary. The “three thousand realms in one thought-moment” represents not only the ontological basis for the actualization of Buddhahood, but also a “contemplation method” (kanpō). In this sense, as we have seen, Nichiren distinguishes his method of contemplating ichinen sanzen as that of “actuality” (ji), from the method of Chih-i and Saichō, which he terms that of “principle” (ri).The latter of course refers to the introspective method set forth in the Mo-ho chih-kuan, in which the practitioner’s (deluded) thought of one moment is taken as the object of contemplation. But what did Nichiren mean in saying that his was the method of “actuality”? While the notion of “actuality” or ji in Nichiren’s thought has undergone extensive interpretation, there is one particular sense of ji to which Nichiren himself calls attention in this context. In the Kanjin honzon shō, he writes that while Hui-ssu and Chih-i had established the teaching of three thousand realms in one thought-moment, “[T]hey only discussed it as inherent in principle (rigu)” and did not reveal “the five characters of Namu-myōhō-renge-kyō, which represents concrete practice (jigyō), or the object of worship of the teaching of origin. “141 Here, ji clearly carries the Mikkyō connotation of jisō, or “actual forms”—the mūdras, mantras, and mandalas employed in esoteric practice. In Nichiren’s Buddhism, the three thousand realms in one thought-moment takes concrete, “actual” form as the daimoku and a specific object of worship (honzon). These two, together with the ordination platform (kaidan) or, more broadly, the place of practice—constitute what Nichiren called the “three great matters of the ‘Fathoming the Lifespan’ chapter of the origin teaching” (honmon juryōhon no sandaiji) or, as the later tradition would call them, the “three great secret Dharmas” (sandai hihō). In Nichiren’s system, these three form the content of the transmission conferred by Śākyamuni Buddha upon Bodhisattva Superior Conduct at the assembly in the air above Eagle Peak and are destined expressly for the Final Dharma age. All three are entailed in the moment of “embracing” the Lotus Sūtra. (Page 266-267)

It will also be noted … that Nichiren reads ichinen sanzen primarily in terms of the mutual encompassing of the ten realms (jikkai gogu). Elsewhere in the same text, he writes, “The three thousand worlds in one thought-moment begins with the mutual encompassing of the ten realms,” that is, the nonduality and mutual inclusion of the nine realms of deluded beings and the enlightened realm of the Buddha. Nichiren specifically identified the mutual encompassing of the ten realms as the ground of the Lotus Sūtra’s two great revelations on which claims for its superiority were based: that persons of the two vehicles have the capacity to attain Buddhahood, and that the Buddha originally realized enlightenment in the inconceivably remote past yet ever since has remained constantly in the world to preach the Dharma. Nichiren saw the promise of Buddhahood given to persons of the two vehicles in the trace teaching as indicating that the nine realms of unenlightened beings encompass the Buddha realm (kukai soku bukkai), and the eternity of the Buddha’s presence set forth in the origin teaching as indicating that the Buddha realm encompasses the nine realms of deluded beings (bukkai soku kukai), both of these expressing the principle that a single thought-moment is the three thousand realms. Thus in Nichiren’s system, the “three thousand realms in one thought-moment”— represented by the mutual inclusion of the ten realms—becomes both the “deep structure” of the entire Lotus Sūtra and the ontological basis upon which the realization of Buddhahood can occur. (Page 266)

It should be noted that, in the context of the Kaimoku shō, this “true ichinen sanzen,” the mutual encompassing of original cause and original effect that is “hidden in the depths” of the “Fathoming the Lifespan” chapter, comes as the culmination of a discussion of five successive levels of teaching, codified by later Nichiren scholars as the “fivefold comparison” (gojū sōtai). Though he did not state so explicitly, Nichiren was in effect here establishing his own doctrinal classification (kyōhan). In so doing, he drew on both traditional T’ien-t’ai categories and the medieval Tendai of his own day, assimilating them to his own insights. The five steps of the comparison are: (1) Buddhist teachings surpass those of non-Buddhist traditions, such as Confucianism and Brahmanism (naige sōtai); (2) within Buddhism, Mahāyāna surpasses Hinayāna (daishō sōtai); (3) within the Mahāyāna, the Lotus Sūtra, being true, surpasses the other sūtras, which are provisional (gonjitsu sōtai); (4) within the Lotus Sūtra, the origin teaching surpasses the trace teaching (honjaku sōtai); and (5) within the origin teaching, “contemplative insight” (kanjin) surpasses the written text (kyōsō). From the standpoint of the sūtra text, the “Fathoming the Lifespan” chapter reveals that Śākyamuni Buddha first achieved Buddhahood countless kalpas ago; yet, however inconceivably distant, that Buddhahood nonetheless had a beginning in time and represents the fruit of a linear process of cultivation. From the standpoint of kanjin, however, the same “Fathoming the Lifespan” chapter is seen to reveal the mutual encompassing of the beginningless nine realms and the beginningless Buddha realm, or the simultaneity of original cause and original effect. Unlike some of the later, more extreme medieval Tendai thinkers, Nichiren never regarded kanjin as a separate transmission independent of the Lotus Sūtra; the realm of “original cause and original effect” is always mediated by the sūtra text. (Page 265)