While it is impossible in a short space to do full justice to Nichiren’s concept of the daimoku, two aspects of it will be outlined here: the daimoku as perfectly inclusive, and the daimoku as the seed of Buddhahood.

The daimoku, which Nichiren equates with the one vehicle, is all-encompassing, a claim he develops from several interrelated perspectives, beginning with his early writings. For example, in the Hokke daimoku shō, the daimoku is said to contain all teachings:

“The teachings of the seven Buddhas and the thousand Buddhas of the past, and of all the Buddhas since long kalpas ago, as well as the sūtras preached by the Buddhas of the present throughout the ten directions, are all followers of the single character kyō [sūtra] of the Lotus Sūtra. … Within this single character kyō [of myōhō-renge-kyō] are contained all the sūtras in the dharma realms of the ten directions.”

In a yet more encompassing sense, the daimoku contains, or rather is, the entirety of the dharma realm. Another passage of the same text reads:

“The five characters myōhō-renge-kyō … contain all sentient beings of the nine realms and also the Buddha realm. And because they contain [all beings of] the ten realms, they also contain the lands of the ten realms, which are those beings’ dependent recompense.”

Or in greater detail, from an earlier, 1260 writing:

“The doctrines of three thousand realms in one thought-moment and the Buddha’s enlightenment in the distant past, the core of the ‘Skillful Means’ and ‘Fathoming the Lifespan’ chapters, are contained within the two characters myōhō [Wonderful Dharma]. … All Buddhas and bodhisattvas, the causes and effects of the ten [dharma] realms, the grasses and trees, rocks and tiles throughout the ten directions— there is nothing that is not included in these two characters. … Therefore, the merit of chanting the five characters myōhō-renge-kyō is vast.”

Here the daimoku is equated with three thousand realms in one thought moment, the entirety of all that is. This identification can be found in some of Nichiren’s earliest writings. (Page 267-268)

From his earliest writings, Nichiren discusses “the daimoku in five or seven characters” as something far more potent than the mere title of a text. The Hokke daimoku shō (On the title of the Lotus), written in 1266, one of his earliest extended discussions of the subject, defines it as “the heart of the eighty-thousand holy teachings and the eye of all the Buddhas.” This theme continues throughout his later writings as well. “People today think that myōhō-renge-kyō is just a name, but that is not so. … [I]t is neither the text nor the meaning but the heart of the entire sūtra.” Here Nichiren drew on the Chinese tradition of title exegesis, in which the entire meaning of a particular sūtra was held to be encompassed by its title. Chih-i, for example, had organized the major portion of the Fahua hsüan-i, his commentary on the Lotus Sūtra, as a discussion of the five characters that comprise the sūtra’s title. (Page 267)

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)

Nichiren elaborates (see earlier) in the following passage:

“When one arrives at the origin teaching, because [the view that the Buddha] first attained enlightenment [in this lifetime] is demolished, the fruits of the four teachings are demolished. The fruits of the four teachings being demolished, their causes are also demolished. The causes and effects of the ten realms of the pre-Lotus Sūtra and trace teachings being demolished, the cause and effect of the ten realms of the origin teaching are revealed. This is precisely the doctrine of original cause (hon ‘in) and original effect (honga). The nine realms are inherent in the beginningless Buddha realm; the Buddha realm inheres in the beginningless nine realms. This represents the true mutual inclusion of the ten realms, the hundred realms and thousand suchnesses, and the three thousand realms in one thought-moment.”

To unpack the rather technical language of this passage, the “four teachings” here represent those other than the Lotus Sūtra. Their “effects” refers to the attainment of Buddhahood, or to the Buddhas, represented in these teachings, and their “causes,” to the practices for attaining Buddhahood, or to those still in the stages of practice. In terms of the ten dharma realms, “cause” represents the nine realms, and “effect,” the Buddha realm. “Demolishing” the causes and effects of the pre-Lotus Sūtra teachings and the trace teaching of the Lotus Sūtra means to demolish linear views of practice and attainment, in which efforts are first made and then Buddhahood is realized as a later consequence. The origin teaching   specifically, the “Fathoming the Lifespan” chapter with its revelation of the Buddha’s original enlightenment   is here seen as opening a perspective in which cause (nine realms) and effect (Buddhahood) are present simultaneously. It is passages such as this that led Tamura Yoshirō to assert that Nichiren maintained the notion of original enlightenment in the depths of his mature thought. (Page 264-265)

In a letter to a follower Nichiren wrote:

“There are two methods of contemplating the three thousand realms in one thought-moment. One is that of principle (ri), and the other that of actuality (ji). In the time of T’ien-t’ai [Chih-i] and Dengyo [Saichō], that of principle was appropriate. Now is the time for that of actuality. Because this [form of] contemplation is superior, the great ordeals [attending its propagation] are also more severe. One [i.e., that of principle] is ichinen sanzen of the trace teaching (shakumon), while the other is ichinen sanzen of the origin teaching (honmon). They differ, differ vastly, like heaven and earth.”

“Now” is of course the Final Dharma age: Nichiren’s “three thousand realms in one thought-moment” represents teaching and practice expressly for the time of Mappō. But what exactly is the “vast difference” he claims between his teaching of ichinen sanzen and that of the earlier T’ient’ai/Tendai masters?

First of all, the passage just cited alludes to a difference in textual locus. … Chih-i derived the concept of the three thousand realms in one thought-moment from the trace teaching or first fourteen chapters of the Lotus Sūtra; it represents his attempt to conceptualize the “true aspect of the dharmas” (shohō jissō) referred to in the “Skillful Means” chapter. For Nichiren, however, this doctrine “is found only in the origin teaching of the Lotus Sūtra, hidden in the depths of the text of the ‘Fathoming the Lifespan’ chapter.” This shift of textual grounding for the ichinen sanzen doctrine is related to the larger context of medieval Tendai thought, which … saw the latter part of the sūtra as superior to the former in its revelation of nonlinear, original enlightenment. (Page 264)

[I]t is the “outer” soteric modality of giving one’s life for the Lotus Sūtra that frames the story of Nichiren’s career. His refusal to compromise his exclusive devotion to the Lotus, his conviction in his unique mission, his intemperate attacks on influential clerics and deliberate provoking of authorities, and his fortitude in the face of danger and privation left for his followers a model of “not begrudging bodily life,” and the persisting charisma of his image as prophet, martyr, and emissary of the Buddha formed the pivot around which the later Nichiren tradition would define its identity. However, behind Nichiren’s mandate that one should be ready to give one’s life for the Lotus Sūtra lies the question of what exactly about the Lotus Sūtra he thought worth dying for. This brings us to Nichiren’s “inner” soteric modality, that of realizing Buddhahood in the moment of chanting the daimoku that lies at the heart of his mature teaching. (Page 264)

“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)

“Nichiren is not the founder of any school,” he wrote, “nor is he a leaf at the tip [i.e., of the branch of some existing school].” The Lotus Sūtra as he understood it was Buddhism, the ocean in which the teachings and practices of the various schools would be absorbed. In later life, he distanced himself from the esoteric Tendai of his own day and denounced earlier Tendai prelates such as Enchin, Ennin, and Annen for adulterating the Lotus-based Tendai teaching with esoteric teachings. On the one hand, he clearly considered himself heir to the earlier tradition of Chih-i and Saichō: “Nichiren of Awa Province has reverently received the transmission from the three teachers [Śākyamuni, Chih-i, and Saichō] and assists the spread of the Hokke lineage in the Final Dharma age,” he wrote. “Together we are the four teachers in three countries.” Such passages have led some to see Nichiren as attempting to revive a “pure” Tendai independent of esoteric accretions. There is no doubt that Nichiren saw himself as standing within the Tendai tradition. Nevertheless, in claiming possession of a Dharma teaching that (1) was received directly from Śākyamuni; (2) was intended specifically for the Final Dharma age; and (3) was to assume a concrete form—as the daimoku, the object of worship, and the ordination platform—that had never before been revealed and transmitted, it appears that Nichiren was in effect establishing a new religion. This distinctive doctrinal basis, along with Nichiren’s fierce emphasis on devotion to the Lotus alone; the charisma of his image, which survived his death, as prophet, martyr, and messenger of the Buddha to the Final Dharma age; the establishment of ordination rites for his clerical followers independent of those of Mt. Hiei; and the formation among his followers of lay patronage networks independent of older religious institutions enabled the emergence and survival of a new sect. (Page 261-262)