After the death of Nichiren （1222-1282）, the history of Nichiren Buddhism doctrinal study in the early modern period was characterized by a shift from the adoption of Japanese medieval Tendai doctrinal thought to Chinese early Tiantai doctrinal study since the Azuchi-Momoyama period. The presence of Ichinyoin Nichijū 一如院日重 （1549-1623） was significant in this era.
The origins of Nichijū’s doctrinal thought have traditionally been thought to lie in the Sankō mushi-e三光無師会 lectures held by Busshinin Nichikō 仏心院日珖 （1532-1598） and others. However, the substance of the Sankō mushi-e is unknown.
I have extracted the descriptions of the Sankō mushi-e lectures found in Nichijū’s Kenmonguanki 見聞愚案記, according to the historical fact that Nichijū participated in the Sankō mushi-e. As a result, it is confirmed that lectures on Tendai studies, scripture reading, and the interpretation of the Lotus Sūtra were held at the Sankō mushi-e. In particular, it can be pointed out that the lectures on Tendai studies were an examination of Chinese early Tiantai doctrinal study, focusing on the three major commentaries of the Tiantai school, Mohe zhiguan 摩訶止觀, Fahua xianyi 法華玄義 and Fahua wenju 法華文句.
