 It is clear that T’oegye stressed the role of Principle in the path to self-cultivation because of its autonomous character. He prescribed that self-cultivation could be attained only by redirecting the blind orientations of Vital Force and nourishing human nature via the practice of “Reverent Mindfulness” (kyŏng 敬). In the Ten Diagrams of Sage Learning, T’oegye suggests that “Reverent Mindfulness is the beginning and the completion of the sage learning” (Yi Hwang [T’oegye] CW, Vol. 1, Book 7, 203a). This has two aspects, external and internal: Externally, Reverent Mindfulness is always informed and constrained by the Confucian ideal of good behavior conforming to the strict adherence of the rules of propriety (Chung 1995: 134). Thus, Reverent Mindfulness involves being “cautious and watchful in the hidden, secluded places” as well as being “properly ordered and controlled, grave and quiet”. Internally, the practice of Reverent Mindfulness also involves preserving one’s internal refined state. Already in his Four-Seven debate with Kobong, T’oegye suggested that Reverent Mindfulness is achieved when the original state of heart/mind is maintained by “concentrating on one thing without departing from it” and also by “regulating the exterior to nourish the interior” (Yi Hwang [T’oegye] CW, Vol. 1, Book 7, 203b; Kalton 1988, 85–87).