According to Grand Master T’ien-tai, the Lotus Sūtra is hard to have faith in and hard to understand because what is preached in both the essential and theoretical sections of the sūtra are altogether different from what is preached in those sūtras expounded before the Lotus Sūtra. Grand Master Chang-an states: “The doctrine of ‘mutual possession of ten realms’ (jikkai gogu) is the very reason why the Buddha appeared in the world. How can we ordinary people be expected to put faith in the Lotus Sūtra and comprehend it easily?” Grand Master Dengyō maintains: “This Lotus Sūtra is most difficult to believe in and comprehend, because the sūtra preaches the true intent of the Buddha.”

Kanjin Honzon-shō, A Treatise Revealing the Spiritual Contemplation and the Most Verable One, Writings of Nichiren Shōnin, Doctrine 2, Page 133-134