As a result of having practiced asceticism at Mt. Hiei seeking the true teaching of Shakyamuni, Nichiren considered what Tendai Daishi called the Kyoso hanjaku (evaluation of sutras) (Buddhist Doctrines known as "Fivefold Periods and Eight Teachings") to be a correct one, reached the conclusion that Hokke-kyo Sutra was the true teaching of Shakyamuni, and began to do shakubuku with the four dictums (of Nichiren Buddhism) according to "Fivefold Periods and Eight Teachings."
釈尊の真の教えを求めて比叡山にて修行を積んだ結果、天台大師のいう教相判釈（五時八教説）が正しいものと考え、法華経が釈尊の真の教えであるとの結論に達し、五時八教説に依って四箇格言を掲げて折伏を行うようになった。