First, the subtle Track of Real Nature shows that although sentient beings originally possessed the treasure of the Buddha-nature, they were not aware of this fact before the Buddha expounded the Lotus Sūtra. Thus, the Track of Real Nature in the various teachings of the Buddha before the Lotus Sūtra is coarse. Upon the revelation of the One Buddha vehicle in the Lotus Sūtra, the practitioners of the other three teachings are able to see the Buddha-nature as the treasure of enlightenment they inherently possess, whereby the coarse dharma in the past becomes the subtle dharma in the present. Second, the Track of the Illumination of Wisdom is subtle if one abandons one’s attachment to striving to attain wisdom and reach truth. One should understand that wisdom and truth are inseparable, and it is false to seek outwardly instead of inwardly, in view of the fact that one’s wisdom is always contained in one’s nature. As long as one realizes that truth and wisdom are identical to each other as one entity, this realization implies that the Track of the Illumination of Wisdom is subtle, representing One Great Vehicle that is neither horizontal nor vertical. Third, the subtle Track of Accomplishment delineates that innumerable practices and dharma-doors, which are contained in the tathāgatagarbha are, by nature, the manifestation of the suchness of the Buddha-nature. With such an understanding, all expedient vehicles become subtle, and there is no more relative, only the ultimate. (Vol. 2, Page 251)