This paper serves as an initial step toward elucidating the formation of Zhu Xi’s cultivation theory. The author raises the need for existing research on the Zhu’s theory to be revised by presenting a counterexample: Zhu’s zhongshu 忠恕 debate in 1158. Both philosophical notions dao 道 and zhongshu are referred in the Lunyu 論語 and the Zhongyong 中庸, but their relationships are described differently. In contrast to Hu Xian, Wu Jinglao and Fan Rugui who equally treated zhongshu as a practice (...) for learners and as distinct from the dao of saints, Zhu divided zhongshu into that of saints and that of learners. According to Zhu, Hu and others’ perspectives separate saints from their daily lives, elevating them to a transcendent position that can never be reached through daily practice. Zhu emphasized that saints are also beings who live their daily lives normally, and that learners can become saints through gradual zhongshu practice. Considering that Li Tong acknowledged Zhu’s understanding of zhongshu, it can be assumed that this perspective of Zhu was formed under the guidance of Li. If so, the existing view that Li insisted on the cultivation theory of the Daonan 道南 school or that Zhu was immersed in Reality-Watching practice needs to be reconsidered. (shrink)