Nichiren had taught that Buddhism for the time of mappō consisted in essence of “three great secret Dharmas” (sandai hihō) implicit in the depths of the origin teaching (honmon) of the Lotus Sūtra—the “origin teaching” being the latter half of the sūtra, which presents itself as the teaching of an eternal Buddha who constantly abides in this world. These three secret Dharmas are (1) the daimoku, or invocation of the Lotus Sūtra’s title, “Namu-myōhō-renge-kyō,” the central practice of Nichiren’s Buddhism and said by him to encompass all the eternal Buddha’s merits and virtues; (2) the object of worship (honzon), the calligraphic maṇḍala that Nichiren had devised, depicting the assembly of the Lotus Sūtra as the eternal Buddha’s enlightened realm; and (3) the “ordination platform.” The first two Nichiren had himself discussed in detail. But, while some of his later writings make reference to the “ordination platform of the origin teaching” (honmon no kaidan), no authenticated work of his explains precisely what he meant by this. Only this one writing, the Sandai hihō shō, clearly presents it as an officially sponsored ordination platform, to be erected in the future when “the ruler and his ministers” have embraced the Lotus Sūtra.

However, the Sandai hihō shō does not survive in Nichiren’s handwriting, and in the modern period his authorship has been heatedly disputed. In particular, in the years following Japan’s defeat in the Pacific War, in the mood of revulsion against institutional Buddhism’s support for the nation’s ill-judged imperialist venture, some scholars of the Nichiren tradition denounced the work as a forgery and denied that Nichiren would ever have embraced a state-sponsored kaidan as a religious ideal. Nonetheless, from the time of Buddhism’s introduction to Japan in the sixth century, the ordination of monks had at least in principle been regulated by the imperial court, and the four ordination platforms existing in Nichiren’s day were all court sponsored. He and his rather marginal religious community existed outside this official system of ordination, and it seems quite possible—whether he personally wrote the Sandai hihō shō or not—that he envisioned the establishment of an “ordination platform of the origin teaching” mandated by the court and the Bakufu, the two ruling structures of his day, as symbolic of the official acceptance of his Buddhism. Whatever Nichiren’s own views, throughout premodern times, the future establishment of an imperially mandated kaidan was widely accepted within the Nichiren tradition as a task whose achievement Nichiren had entrusted to his later followers. Rival lineages sometimes debated over whose head temple would house the eventual kaidan structure. Yet at the same time, perhaps in part because the likelihood of realizing this goal seemed so remote, a corollary interpretation emerged in which the honmon no kaidan referred simply to that place, wherever it might be, where the follower of Nichiren embraces faith in the Lotus Sūtra and chants Namu-myōhō-renge-kyō—a reading closely linked to Nichiren’s own claim that wherever one chants the daimoku of the Lotus Sūtra is the Buddha land. Under the rule of the Tokugawa shogunate in the early modern period (1603-1868), when religious proselytizing was severely restricted, this abstract interpretation of the kaidan became the predominant one. Not until the Meiji period (1868-1912), with a radical restructuring of Japan’s government, would the ideal of an imperially sponsored kaidan be reimagined as something achievable in concrete terms.