Chu-chi Yung-pen (Abiding in the Traces and employing the Origin) is the function related to the Subtlety of the Original Life-span and the Subtlety of the Original Retinues. Chih-i illustrates that the Buddha not only reveals the Origin but uses it as well. Although he abides in the Traces, manifesting birth and death numerous times, this manifestation of life and death is actually the manifestation of the Original Life-span. Moreover, the Traces are represented by the disciples as the Three Vehicles that belong to the Original Retinues.