Jinul (whose name is spelled Chinul under the McCune Reischauer Romanization system), a Korean Buddhist monk of the Goryeo period, is considered by many scholars to be the most influential figure in the formation of Korean Seon Buddhism. Deeply disturbed at the degree of corruption that had crept into the Buddhist monastic system, he sought to establish a new movement that he called the samādhi and prajñā society. The goal of this organization was the establishment of a new community of disciplined, pure-minded practitioners deep in the mountains. Jinul eventually brought this mission to fruition with the founding of the Seonggwangsa monastery at Mount Jogye, which still serves as an center for Korean Seon practice.

A major issue that received special attention from Jinul was the relationship between so-called gradual and sudden approaches to Buddhist practice and enlightenment. Drawing on various Chinese treatments of this...