The … elaboration of the meaning “subtle” paves the way to Chih-i’s own interpretation of the Lotus Sūtra, which is his attempt to establish the Lotus Sūtra as the doctrinal foundation for his system of understanding Buddhism. This is because the most significant feature of the Lotus Sūtra concerns the Ultimate Truth as the Buddha vehicle that embraces all types of the Buddha’s teaching. With the One Buddha-vehicle as the unifying force, Chih-i is able to incorporate different viewpoints, to classify the teaching of the Buddha, to reconcile differences among various divisions of Buddhism, and to give a reasonable explanation of various theories that are held by different schools. By doing so, Chih-i demonstrates that Buddhism can be viewed as a whole, and that various doctrines and theories of practice that are apparently contradictory to each other are in fact coherent, for they are part of the scheme in the Buddha’s teaching. Chih-i’s endeavor of establishing a coherent system of presenting Buddhism as a whole reflects the need of his time that calls for the unification of the Buddhist world in Southern and Northern China (as we have mentioned in the background introduction in Chapter One of Volume I). Chih-i’s effort of establishing a coherent system of understanding Buddhism may be driven by his own religious devotion as well as his own realization of the Lotus teaching. Having fully digested the teaching expressed in different Buddhist scriptures, Chih-i must have felt obligated to use his talent to take upon himself the huge task of systematizing the teaching of the Buddha, in order to reconcile contradictory views among various Buddhist schools, and to assure that Buddhism, as a whole, would further flourish in Chinese soil. (Vol. 2, Page 67-68)