How can Nichiren insist that the Lotus Sūtra is the only sole sūtra that is difficult to receive and keep, read, recite, expound, and copy in the Latter Age after the Buddha’s passing?

In order to evaluate these claims, Nichiren refers to the first and last of the “four reliances” taught by the Buddha in the Mahāyāna Mahāparinirvāṇa Sūtra as a guide for discerning the meaning of Buddhist teachings. The four reliances are to: “Rely on the Dharma and not upon persons; rely on the meaning and not upon the words; rely on wisdom and not upon discriminative thinking; rely on sūtras that are final and definitive and not upon those which are not final and definitive.” (see Yamamoto, p. 153)

Nichiren takes the four reliances to mean that one should not trust the word of even great bodhisattvas like Samantabhadra or Mañjuśrī unless they are preaching with the sūtras in hand. Nichiren cites Nāgārjuna (late second to early third century), Zhiyi (538-597), Saichō (767-822; also known as Dengyō), and even Enchin (814-891; aka Chishō) who all state that one should only follow commentaries that accord with what is taught in the sūtras and furthermore that one should not believe in oral transmissions. All of these teachers are considered to be patriarchs of the Tiantai/Tendai school and therefore Nichiren is showing that the interpretations of the Tiantai school can be relied upon because they follow the principles of the four reliances. Nichiren’s contention is that the other schools of Buddhism were straying from these principles, because of sectarian pride in their own particular doctrines and methods. Though it might seem ironic to those who believe that Nichiren was himself a sectarian polemicist, he wrote, “Surely, those who aspire to enlightenment should not be biased, stay away from sectarian quarrels, and not despise other people.” (Hori 2002, p. 85) Nichiren did not see himself as trying to promote his own narrow view, or even the particular views of the Tiantai school. Rather, Nichiren was trying to find in the sūtras themselves the criteria for judging the relative merits of various Buddhist teachings. He believed that he had found such a criteria in the four reliances and in the statements of the Lotus Sūtra regarding its own supremacy. Nichiren’s conviction was that in China only the Tiantai school had upheld what the sūtras actually teach, and that in Japan, only Saichō and himself had properly passed on this teaching without distorting or compromising it.