QUESTION: How does the term “1,000 aspects contained in 100 realms” (hyakkai senyo) differ from “3,000 existences contained in one thought” (ichinen sanzen)?

ANSWER: Speaking of a mind having “1,000 aspects contained in 100 realms,” we consider sentient beings only. When we talk about “3,000 existences contained in one thought,” we consider both sentient as well as insentient beings.

Kanjin Honzon-shō, A Treatise Revealing the Spiritual Contemplation and the Most Verable One, Writings of Nichiren Shōnin, Doctrine 2, Page 130