The subtlety of the dharma is illustrated by the Ten Subtleties in the door of the Traces and in the door of the Origin. The door of the Traces (Chi-men) is the theme of the first fourteen chapters of the Lotus Sūtra, in which the Buddha presents himself as the historical manifestation, Śākyamuni. The door of the Origin (Pen-men) is the theme of the latter half of the Lotus Sūtra, in which the fundamental and eternal Buddha is for the first time displayed. The Ten Subtleties in the Traces are elucidated under five divisions. The Ten Subtleties in the Origin are interpreted in ten aspects. The category of the Ten Subtleties is Chih-i’s endeavor to incorporate all the theories and divisions in Buddhism, so that Buddhism can be presented as a coherent whole, constituted by the cause and effect of Buddhahood. (Vol. 2, Page 90)