Nichiren’s writings say very little about the place of his mandala (or of Buddha images) in actual practice. There is one personal letter, the “Nichinyo gozen gohenji,” which does touch on this issue, and though some modern scholars dispute its authenticity, it has historically been highly valued in the Nichiren tradition for its easily accessible description of the mandala and its relation to the practitioner’s faith:

Never seek this gohonzon elsewhere, [for] it abides only in the fleshly heart within the breast of persons like ourselves who embrace the Lotus Sūtra and chant Namu-myōhō-renge-kyō. This is called the capital city of suchness, the ninth consciousness that is the mind-ruler (kushiki shinnō shinnyo no miyako). Being endowed with the ten realms means that [all] ten realms, not excepting a single one, are contained within a single realm, [that of Buddhahood]. That is the reason why this is called a mandala. “Mandala” is a word from India. Here [in Japan] it is called “perfect endowment” (Tinnen gusoku) or “cluster of merits” (kudokuju). This gohonzon is contained solely within the word “faith.” That is the meaning of “gaining entrance by faith.” By believing undividedly in [the Lotus Sūtra, in accordance with its words,]” honestly discarding skillful means” and “not accept[ing] even a single verse from other sūtras, ” Nichiren’s disciples and lay followers shall enter the jeweled stūpa of this gohonzon. How reassuring, how reassuring!

If one judges by this passage, it appears that the logic of Nichiren’s mandala is quite similar to that of esoteric practice, wherein the practitioner visualizes the union of self and Buddha, known as “the Buddha entering the self and the self entering the Buddha” (nyūga ganyū). For Nichiren, however, the nonduality of the practitioner and the Buddha is realized neither by esoteric visualization techniques nor by introspective contemplation involving the application of mental categories, such as the threefold contemplation. Rather, it is by faith in the Lotus Sūtra that one enters the realm of the Buddha’s enlightenment–the three thousand realms in a single thought-moment as actuality–and manifests its identity with oneself. (Page 280-288)

Nichiren’s mandala includes not only Buddhas, bodhisattvas, and deities but also representatives of the evil realms, such as rākṣasa demons and the treacherous Devadatta. In including such figures, Nichiren followed not the text of Lotus Sūtra itself–in which all beings in the six realms of transmigration are removed before the jeweled stūpa is opened–but the principle of three thousand realms in one thought-moment, according to which even the Buddha realm contains the nine unenlightened states. In short, the mandala depicts the mutual inclusion of the ten realms. As noted above, Nichiren saw this concept as central to the three thousand realms in a single thought-moment, an emphasis visible in the mandala. A writing attributed to Nichiren explains:

The “Jeweled Stūpa” chapter states: “All in that great assembly were lifted and present in open space.” All the Buddhas, bodhisattvas, and great saints, and in general all the beings of the two worlds [of desire and form] and the eight kinds of [nonhuman] beings who assembled in the introductory chapter, dwell in this gohonzon, without a single exception. Illuminated by the light of the five characters of the Wonderful Dharma, they assume their originally inherent august attributes. This is called the object of worship. (Page 277-278)

[T]he object of worship not only is held physically to embody the three thousand realms in one thought-moment but also represents an attempt to depict this reality visually. In the case of configurations of statues, this enlightened reality of the eternal Buddha, described in the Lotus Sūtra as the assembly in open space above Eagle Peak, is only suggested by the presence of the Buddha’s original disciples, the four bodhisattvas, or by the two Buddhas, Śākyamuni and Many-Jewels (Prabhūtaratna, Tahō), seated side by side in the jeweled stūpa. Nichiren’s mandala, however, is much more detailed. Namu-myōhō-renge-kyō is written vertically in large characters down the center. At the top, this central inscription is flanked by the two Buddhas, Śākyamuni and Many Jewels, who are in turn flanked by the four bodhisattvas. Below them, in the next row, are representatives of the bodhisattvas who are followers of the Buddha of the provisional and trace teachings, such as Fugen (Samantabhadra) and Monju (Mañjuśrī), and the great voice-hearers, Śāriputra and Maudgalyāyana, flanked by the Buddhist tutelary deities Brahmā and Indra, and King Mara of the deva realm. In lower rows still are representatives of the six realms: the devas of the sun, moon, and stars, King Ajātaśatru, the wheel-turning king, the asura king, the dragon king, the raksasa Kishimojin (Hariti) and her ten daughters, and the Buddha’s cousin and traitorous disciple Devadatta. Also represented in the assembly are the sun goddess Tenshō Daijin and Hachiman Daibosatsu, who for Nichiren together represented the kami of Japan. Beside them, the patriarchs T’ien-t’ai Ta-shih (Chih-i) and Dengyō Daishi (Saichō) are also accorded a place. The four deva kings guard the four corners of the mandala, and to either side appear the Siddham “seed characters” for the esoteric deities Fudo Myōō and Aizen Myōō, representing, respectively, the doctrines of “saṃsāra is nirvāṇa” (shoji soku nehan) and “the defilements are bodhi” (bonnō soku bodai). Passages from the sūtra, expressing its blessings and protection, are inscribed to the right and left sides of the assembly; the choice of inscriptions sometimes varied according to the individual mandala. At the bottom is Nichiren’s signature and the words: “This is the great mandala never before revealed in Jambudvipa during the more than 2,220 years since the Buddha’s nirvāṇa.” (Page 277)

Nichiren spoke of his object of worship as embodying “the three thousand realms in a single thought-moment as actuality,” a statement that may be understood in two ways. First, as underscored by recent studies in Buddhist art history, icons and mandalas in premodern Japan were seen not as merely symbolic or representational but as participating in and actively embodying the sacred powers of the beings or principles they depicted. Nichiren explains this idea in terms of the concept of the Buddhahood of grasses and trees (sōmoku jōbutsu), or more broadly, of insentient beings, a principle encompassed by the doctrine of the three thousand realms in one thought-moment:

Both inner and outer writings permit the use of wooden and painted images as objects of worship, but the reason for this has emerged [only] from the T’ien-t’ai school. If plants and trees did not possess cause and effect [i.e., the nine realms and the Buddha realm] in both physical and mental aspects, it would be useless to rely on wooden and painted images as objects of worship. … Were it not for the Buddha-seed which is the three thousand realms in one thought-moment, the realization of Buddhahood by sentient beings and [the efficacy of] wooden and painted images as objects of worship would exist in name but not in reality.

For this reason, Nichiren insisted that only the Lotus Sūtra, the textual source of the ichinen sanzen principle, was efficacious in the eye-opening ritual for consecrating Buddha images. (Page 276-277)

“In the precept lineage [kaike],” Kōen writes, “the profound Ultimate is transferred by means of concrete ritual forms (jisō).” The most distinctive ritual form of the kai kanjō is its elaborations of the mūdra of the palms placed together (gasshō). This mūdra, says Kōen, was performed by Śākyamuni and Many Jewels in the jeweled stūpa and represents the fusion of the object of contemplation and the wisdom that realizes it (kyōchi myōgō), as well as the supramundane truth and the worldly truth being a single suchness (shinzoku ichinyo). Cause and effect, dependent and primary recompense, the single thought-moment and the three thousand realms, yin and yang–all dharmas are encompassed in the gesture of gasshō, which is called the “mūdra of the true aspect” (jissō no in). The Enkai jūroku chō elaborates three kinds of gasshō corresponding to the “three kinds of Lotus Sūtra,” the classification of the Buddha’s teachings employed by Saichō to subsume them within the One Vehicle. (Page 136)

The present study has approached hongaku thought as representative of a new paradigm or “reimagining” of liberation that emerged and became influential in the early medieval period. This paradigm was characterized by nonlinearity, that is, by the conviction that enlightenment is directly accessible in the present moment, and that practice represents the expression of enlightenment, not merely the means to achieve it. This way of thinking about Buddhist liberation also stressed dependence upon a single factor, whether faith, insight, or a specific practice; access ibility, at least in theory, to all persons, even (or especially) those of limited capacity; and a deemphasis on moral cultivation as a causal factor necessary to salvation. This paradigm was shared by both Tendai and the new Kamakura schools. Given the difficulties of chronology, and the fact that the doctrines of medieval Tendai and of the new schools continued to undergo elaboration throughout the Kamakura and Muromachi periods, it is difficult to say that this paradigm simply and unproblematically “emerged” from Tendai. It developed within both Tendai and the new schools and was influenced by their interaction. By the latter medieval period, it had become an orthodoxy. (Page 362)

In medieval Tendai thought, the nonduality of the ordinary worldling and the Buddha forms the focus of argument; the particular form of practice one adopts is less important. In the new movements, this “nondual” standpoint is assimilated to claims for the sole validity of a particular form of faith or practice, which itself becomes the polemical touchstone, as the exclusive validity of the Lotus Sūtra does in the case of Nichiren. But this shift in focus is neither a rejection nor a fundamental transformation of the hongaku stance: Acceptance or denial of original enlightenment thought was not the fault line along which the “old”/”new” divide occurred. Far more important to the emergence of the new movements were such factors as their success in forming new institutions or kyōdan (including, as Matsuo Kenji has noted, the adoption of ordination procedures independent of the state-sponsored kaidan); their grounding in social and economic bases different from those of the Tendai temple-shrine complexes of the capital; and the particular ideological orientation inherent in their commitment to single practice, which served to define them over and against other Buddhists. (Page 361-362)

Chih-i’s own thought stresses that delusion and enlightenment, the nine realms and Buddha realm, are inherent in any phenomenon; thus, those who live in evil circumstances and have no opportunity to contemplate the perfections are not excluded from the Way but can make that evil the subject of liberative contemplation. Nevertheless, he was extremely careful to clarify that the ontological nonduality of good and evil did not obviate the need to make firm conventional distinctions between them; he also inveighed against monks who interpreted the teaching of nonduality as legitimizing antinomian behavior or who taught it irresponsibly without regard for their listeners’ ability to understand. (Page 361)