In Chih-i’s view, track is dharma and dharma is track: “What is called the dharma can be named as the track, which is tracked by all Buddhas in attaining Buddhahood.”

To be specific, the Threefold Dharma, also called Threefold Track (San-kui), refers to the Track of Real Nature (Chen-hsing Kui), the Track of the Illumination of Wisdom (Kuan-chao Kui), and the Track of Accomplishment (Tzu-ch ‘eng Kui). These Three Tracks are Chih-i’s theoretical delineation of the phenomenal world: there are three dharmas that can be tracked and all things in the Ten Dharma-realms contain these three dharmas. In other words, the whole universe is constituted by these Three Tracks. Horizontally, the Three Tracks cover the width of the ten directions; vertically they penetrate the three periods of time, including the beginning as the cause and the end as the effect. According to Chih-i’s definitions, the Track of Real Nature refers to the never-changing true reality of sentient beings that is characterized by non-illusion and non-differentiation; the Track of the Illumination of Wisdom refers to the wisdom that destroys delusions and reveals the real nature of beings; and the Track of Accomplishment concerns the wholesome performance of deeds that is required in realizing this wisdom of penetrating the true reality. The Threefold Track is related to the Buddha-nature as the Triple Cause of Buddhahood. The Track of Real Nature corresponds to the Fundamental Cause (Chen-yin), which refers to the fact that all beings are inherently endowed with the true nature of reality. The Track of the Illumination of Wisdom corresponds to the Understanding Cause (Liao-yin), that is, the inherent potential for wisdom in all sentient beings which allows them to eventually uncover their true nature from within. The Track of Accomplishment corresponds to the Conditional Cause (Yüan-yin), or the inherent potential and propensity for Buddhahood within all sentient beings, which allows them to perform meritorious deeds in order to attain wisdom. According to this definition, Chih-i believes that the Threefold Buddha-nature is an invisible state of Buddhahood that causes the attainment of Buddhahood, and sheds light on the universal salvation of all sentient beings. The Threefold Track, on the other hand, is the visible state as the effect of Buddhahood the ultimate fruition of enlightenment. Chih-i names the Triple Buddha-nature as the “Threefold Track of the Virtue of Nature” (Hsing-te San-kui).

Furthermore, Chih-i’s theory of the Threefold Track attempts to illustrate the One Buddha-vehicle as the core of the teaching of the Lotus Sūtra. Chih-i points out that this One Buddha-vehicle consists of the Threefold Track. Only if the practitioner rides on the vehicle that is formed by the Threefold Track, can he directly arrive at the bodhimaṇḍa and attain perfect enlightenment. This indicates that the Threefold Track is the “Threefold Track of the Virtue of Cultivation” (Hsiu-te San-kui). To Chih-i, the Threefold Track in Buddhism is extremely significant as it reflects all the causes and effects of attaining Buddhahood. Considering that the Threefold Track contains all dharmas from beginning to end, the noumenon and the phenomenon of the universe can all be concluded and delineated by the Threefold Dharma. The Threefold Track that forms the great vehicle can be taken as noumenon, and the Threefold Track that contains all things can be taken as phenomenon. (Vol. 2, Page 239-240)