Number “ten” symbolizes the completion of a concept or the infinity of the universe in Buddhism. The traditional view in Buddhism of the ten directions: east, west, north, south, north-east, north-west, south-east, south-west, above, and below, are intended to encompass the whole space. The concept of the Ten Dharma-realms (i.e., the realms of hell-dwellers, hungry ghosts, animals, asuras, humans, heavenly beings, śrāvakas, pratyekabuddhas, bodhisattvas and Buddhas that are arranged hierarchically), is formulated by Chih-i, and is Chih-i’s system in encompassing the whole universe. Completeness is an important character of Chih-i’s philosophical system. Correspondingly, that the Hsüan-i (Profound Meaning of the Lotus Sūtra) consists of ten volumes can be seen as this symbol of completeness.