The True Meaning and Purpose of All Expedient Means

[O]ther Sūtras clarify the nine [suchlike characteristics of] nature, appearances [and so forth], but do not go so far as to expound that the nature, appearances [and so forth] of the Buddha are [characterized as] an integrated reality simultaneously empty of substantial Being yet conventionally existent. It is this Lotus Sūtra which reveals [the true meaning and purpose of] all expedient means and leads all to attain and enter [the one final goal of Buddhahood]. In their discussion of [suchlike] appearances, nature [and so forth], they do not mention “integrated reality as simultaneously empty yet conventionally existent.” The Tathāgata emphatically praises this Lotus Sūtra as the most supreme, because this meaning is implicit here.

Foundations of T'ien T'ai Philosophy, p 194-195