[The technique of comparison] serves to support Chih-i’s theory taking the Lotus Sūtra as the supreme teaching. By comparing different features between the Lotus Sūtra and other sūtras, the superiority of the former is confirmed.

The most unique feature of the Lotus Sūtra lies in its doctrine of the Ultimate Truth, and this Ultimate Truth is identified by Chih-i with the Middle Way, since the Middle Way, as the principle, represents the Ultimate Truth of Buddhahood. While the theory of the Lotus Sūtra as the supreme teaching is sustained by this method of comparison, the doctrine of the Ultimate Truth in turn provides the foundation for the legitimacy of Chih-i’s own theory of the Middle Way.

A good example of launching a comparison is by presenting an illustration of the Ten Suchnesses in each of the Ten Dharma-realms. As a result of this comparison, the Ten Suchnesses of the Buddha-realm are shown to be the foremost of all suchnesses in whatever realm, in view of the fact that they embody the Buddha’s knowledge and insight (that embrace all dharmas and make no distinction between the two opposite aspects). This is the first level of comparison among the Ten Dharma realms, by which the Buddha Dharma-realm is confirmed as the highest. The second step is to explain why the Buddha praises the Lotus Sūtra as the unsurpassed, by means of judging whether or not the Ten Suchnesses in the nine Dharma-realms (that are exposed in other sūtras) enter the Buddha Dharma-realm. The conclusion is that only in the Lotus Sūtra are the Ten Suchnesses in the nine Dharma-realms converged into the Buddha Dharma-realm. This kind of comparison legitimizes the Lotus Sūtra to be the supreme doctrine. By presenting the Lotus Sūtra as the final teaching of the Buddha, which automatically denote the meaning of perfect and harmonizing, Chih-i ‘s own system of thought is also legitimated with the undertone of perfection, corresponding to what is represented by the Lotus Sūtra. (Page 84-85)