The practices carried out by the Buddha throughout his countless lifetimes (causes) and the resulting virtues of his enlightenment (effects) are contained in the daimoku and spontaneously accessed by the practitioner in the act of chanting. We can see this idea developing in a personal letter that Nichiren wrote the year before the Kanjin honzon shō:

This jewel of [the character] myō contains the merit of the Tathāgata Śākyamuni’s Pāramitā of giving (danbaramitsu), when in the past he fed his body to a starving tigress or [gave his life] to ransom a dove; the merit of his Pāramitā of keeping precepts, when, as King Śrutasoma, he would not tell a lie; the merit gained as the ascetic Forbearance, when he entrusted his person to King Kali; the merit gained when he was Prince Donor, the ascetic Shōjari, [etc.] He placed the merit of all his six perfections (rokudo) within the character myō. Thus, even though we persons of the evil, last age have not cultivated a single good, he confers upon us the merit of perfectly fulfilling the countless practices of the six perfections. This is the meaning [of the passage], “Now this threefold world / is all my domain. / The beings in it / are all my children.” We ordinary worldlings, fettered [by defilements], at once have merit equal to that of Śākyamuni, master of teachings, for we receive the entirety of his merit. The sūtra states, “[At the start I made a vow / to make all living beings] / equal to me, without any difference.” This passage means that those who take faith in the Lotus Sūtra are equal to Śākyamuni Commoners [i.e., the heirs chosen to succeed the emperors Yao and Shun] immediately achieved royal status. Just as commoners became kings in their present body, so ordinary worldlings can immediately become Buddhas. This is what is meant by the heart of [the doctrine of] three thousand realms in one thought-moment.

A third aspect of the all-inclusiveness of the daimoku comes to the fore in Nichiren’s writings after his banishment to Sado. This is the idea that the whole of the Buddha’s enlightenment is contained within the daimoku and accessible to the practitioner in the act of chanting it. This theme is most clearly developed in a passage from the Nyorai metsugogo gohyakusai shi kanjin honzon shō (The contemplation of the mind and the object of worship first [revealed] in the fifth of the five-hundred-year periods following the nirvana of the Tathāgata) or simply Kanjin honzon shō, regarded in the tradition as Nichiren’s single most important writing. In this work, written in question-and-answer style, a hypothetical interlocutor asks what is meant by the “contemplation of the mind” (kanjin). Nichiren responds that it is to “observe one’s own mind and see [in it] the ten dharma realms”—specifically, to see that one’s own mind contains the Buddha realm. Several rounds of further questioning and explanation follow as the hypothetical interlocutor finds it “hard to believe that our inferior minds are endowed with the Buddha dharma realm.” This questioner may perhaps be thought to represent the people of the Final Dharma age, who are not capable of practicing introspective contemplation on the three thousand realms in a single thoughtmoment. Finally, in a passage considered by many within the Nichiren tradition to represent the very core of his teaching, Nichiren indicates that “contemplating the mind” in the Final Dharma age is not a matter of “seeing” the identity of the Buddha realm with one’s own mind in introspective meditation, but of embracing the daimoku, which encompasses Buddhahood within it:

The Wu-liang-i Ching states, “Even if one is not able to practice the six Pāramitās, the six Pāramitās will naturally be present.” The Lotus Sütra states, “They wish to hear to the all-encompassing Way.” … To impose my own interpretation may slight the original text, but the heart of these passages is that Śākyamuni’s causal practices (ingyō) and their resulting merit (katoku) are inherent in the five characters myōhō-rengekyō. When we embrace these five characters, he will naturally transfer to us the merit of his causes and effects.”

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)