Appearing in this world, Śākyamuni Buddha preached many teachings during His lifetime. The Buddha classified His own teachings preached during 50 years into different type of doctrines: shallow and profound, inferior and superior, and expedient and true. He thus preached that the truth was not revealed in the sūtras expounded in the 40 years or so before the Lotus Sūtra was preached, and that the Lotus Sūtra is the supreme and true teaching of all the sūtras expounded in the past, present, and future existences. Moreover, the Buddha of Many Treasures and various Buddhas throughout the universe attested this to be true.

Jōren-bō Gosho, A Letter to Jōren-bō, Writings of Nichiren Shōnin, Volume 5, Page 172