This paper examines the citations of the Shugo kokkaishō 守護国界章 of Saichō in Nichiryū’s 日隆 (1384–1464) writings.
It concludes that Nichiryū quoted the Shugo kokkaishō in order to clearly distinguish the Lotus Sūtra’s Honmon happon (本門八品, the eight chapters 15–22), the true teaching, from other scriptures. And thus we understand that when Nichiryū quotes from the Shugo kokkaishō “The three uncreated bodies are the true Buddha before awakening” and “The three bodies of the Buddha of the True Teaching are cosubstantial and cofunctional (kutai-kuyū, 倶体倶用),” this defines the Sambhogakāya, which has completed the eternal cause revealed in the Lotus Sūtra’s Honmon-happon.
As for why Nichiryū quoted the Shugo kokkaishō, it is inferred that he tried to show the characteristics of Nichiren doctrine in medival Japanese Tendai.
