Kōzōin Nisshin 広蔵院日辰 (1508-1576), who was active in Kyoto during the Sengoku Period, was a well-known scholar monk of the Nichizon monryū school 日尊門流 of the Nichiren sect, and he left many books for the education of the school. This article focuses on an unpublished volume called Ryakunirongi 略二論義 by Nisshin that is kept at the Yōbō-ji 要法寺 in Kyoto, the head temple of the Nichizon monryū school. The Ryakunirongi, a work of discussions on the Lotus Sūtra, is a simplified version of the six volumes of the Kaishakukenpon Hokke nirongi tokuishō 開迹顕本法華二論義得意抄 (also known as Nirongishō 二論義抄), Nisshin’s representative work, which was completed in July 1560. While the Nirongishō explains the contents of the doctrine in detail, the Ryakunirongi was compiled on the assumption that it would be used in debates (rongi 論義) held in public. In such debates, which are ceremonies as well as training for younger monks, it is necessary to ask and answer questions on each chapter of the sūtra for a number of days, and attend lectures. In this article, I consider the formal features of the Ryakunirongi, which was compiled with consideration for the constraints accompanying the actual situation of the debates.