Chigi was a scholar priest who originated a doctrine based on Hokke-kyo sutra, Makahannya haramikyo sutra and Daichidoron (Commentary on the Great Wisdom Sutra) that were translated by Kumaraju as well as Nehangyo sutra, advocated Kyoso hanjaku (theory on the history of sutra establishment) based on Goji hakkyo, which deems Hoke-kyo sutra as paramount, and preached to become Buddha through shikan (Tendai Meditation).
智ギは、鳩摩羅什訳の法華経・摩訶般若波羅蜜経・大智度論、そして涅槃経に基づいて教義を組み立て、法華経を最高位に置いた五時八教という教相判釈（経典成立論）を説き、止観によって仏となることを説いた学僧である。