 Further complicating the intellectual impetus of Korean Confucianism was its reaction to (or rather against) Sinitic Chan meditational developments that shaped the Sŏn school in Korea. Korean Sŏn ideas had arguably reached their maturity in the teachings of the Koryŏ monk Chinul (1158–1210), especially his text On Cultivating the Mind (修心訣, K. Susim kyŏl). Chinul’s approach recognises the mind as the essence (體, K. che) of one’s Buddha Nature, which requires continual practice and cultivation aids to refine its function (用 K. yong), bringing together the important essence-function (che-yong) feature of Korea’s Buddhist tradition, which would deeply influence the Neo-Confucian thought of Chosŏn. The Sŏn practice of seated meditation would also shape Neo-Confucianism’s own mind-focused concept of “quiet-sitting” (靜坐; C. jingzuo, K. chŏngjwa), also known as chŏngjwa chonsim (靜坐存心): to sit quietly and preserve the mind (Palais 1996: 181).