In view of the fact that the Ten Suchnesses represent the Ultimate Truth, and the Ultimate Truth consists of both the Relative and the Ultimate, the Relative and the Ultimate are defined by Chih-i in relation to the Ten Dharma-realms. … [T]he first nine realms are ascribed by Chih-i to the Relative, and the last Buddha-realm to the Ultimate. Among the ten realms, the six realms (hell-dwellers, hungry ghosts, animals, asuras, humans and heavenly beings) are the lower state of existence, and the four realms (śrāvakas, pratyekabuddhas, bodhisattvas, and Buddhas) are the state of sagehood (Liu-tao Ssu-sheng). Since the Ten Dharma-realms are divided into the Relative and the Ultimate, like that of the Ten Suchnesses, the ten realms should also contain the three meanings in terms of the Threefold Truth.

1. With regard to the Ten Dharma-realms that contain the meaning of Emptiness, this means that all ten realms belong to the Dharma-realm (Ch., Fa-chieh; Skt., dharmadhātu), the former relies on the latter (Neng-i), and the latter as the foundation is what the former relies upon (So-i). Thus, the ten realms form the Ten Dharma-realms. All of the Ten Dharma-realms are fundamentally empty and enter the realm of Emptiness (K’ung-chieh).
2. With regard to the Ten Dharma realms that contain the meaning of the Provisional, this refers to the separation of the ten realms (Shih-chieh Chieh-ko) due to their differences between the lower states of existence and the state of sagehood:
   

   “Because of their different lots, separated causes and effects, and distinctive features of the profane and sacred states, the ten realms are differentiated from each other.”

   Their differences are related to the conventional existence, with which the Ten Dharma-realms enter the realm of the Provisional (Chia-chieh).

3. With regard to the Ten Dharma-realms that contain the meaning of the Middle Way, this means that the Middle Way can be inferred from the principle or truth that is embodied by the Ten Dharma-realms:
   

   “These Ten [Dharma-realms] are all identical to the dharmadhātu and encompass all dharmas. All dharmas tend toward hell, and do not transcend this destiny. [The dharmadhātu] itself is the principle [of reality], and since it does not depend on anything, it is called the dharmadhātu. The same is also true [for all destinies] all the way up to the Buddha Dharma-realm.”

   The principle or truth is what the dharmadhātu denotes, and the principle is referred by Chih-i to the Middle Way. Therefore, the Ten Dharma-realms enter the realm of the Middle Way (Chung-chieh).

The connections between the Ten Dharma-realms and the Ten Suchnesses are displayed in a statement by Chih-i:

“One Dharma-realm embraces the Ten Suchnesses, and the Ten Dharma realms embrace one hundred Suchnesses.”

Meanwhile,

“One Dharma-realm embraces the other nine Dharma-realms, and hence, there come to be one hundred Dharma-realms and one thousand Suchnesses.”

(Vol. 2, Page 73-74)