The only way seemingly that leads to Buddhahood is the “3,000 in one thought” doctrine of T’ien-t’ai. However, we in the Latter Age of Degeneration do not possess the intelligence to understand it; nevertheless, among all the sūtras preached by Śākyamuni during His lifetime, only the Lotus Sūtra embodies the gem of the “3,000 in one thought” doctrine. Doctrines of other sūtras may look like gems, but in actuality they are merely yellow rocks. Just as, no matter how hard you squeeze sand, you will not get oil, or barren women will never have children, even wise men will not be able to attain Buddhahood by means of other sūtras. As for the Lotus Sūtra, even ignorant persons will be able to plant the seed of Buddhahood.

Kaimoku-shō, Open Your Eyes to the Lotus Teaching, Writings of Nichiren Shōnin, Doctrine 2, Page 108-109