Fu-chi Hsien-pen (Covering the Traces and revealing the Origin) is the function related to the Subtlety of the Original Supra-mundane Powers. This is spoken of by Chih-i in terms of various expedient means employed by the Buddha in responding to the capabilities of beings. In order to get rid of disciples’ attachment to the Traces, the Buddha covers the Traces and reveals the Origin (for the sake of keeping the Traces for the later use of transforming others), should the necessity arise. (Vol. 2, Page 448)