Number “six” plays an important role in the system of hexagrams in the Book of Changes, which reflects in six lines forming a complete pattern of succession of six positions of Yin and Yang. This suggests that what “six” represents is the completion of the pattern of the universe represented by a hexagram, which is constituted by the doubled three powers (that can refer to heaven, earth, and man). The pattern of the hexagram is formulated by the elements of Yin and Yang, each of which is employed in succession, forming six lines. It is interesting to note that Chih-i uses a similar way to define the Origin and the Traces in terms of using the numerical category of six and in terms of the two elements being employed in succession. This indicates that Chih-i defines the Traces and the Origin in six groups in terms of the six polar concepts (i.e., “principle” and “phenomenal appearances”, “principle” and “teaching”, “teaching” and “practice”, “substance” and “function”, “ultimate” and “relative”, and “present” and “past”), and each of the following groups of definition takes the meaning of its proceeding one. With the employment of these six polar concepts, the Traces and the Origin are defined in succession. Such a way to define the Traces and the Origin denotes a complementary relation between these two entities. Moreover, instead of the two elements of Ying and Yang that constitute the hexagram as the representation of a complete pattern of the universe (possibly intended by Chih-i himself), this pattern is also completed with number six. However, since this pattern is defined in the Buddhist context, it is spoken of in terms of time (embodied by the Traces) and space (embodied by the Origin).