[A]bsolute subtlety (zetsudaimyō) is a doctrine of revealing the truth (single path to enlightenment) and merging all the provisional teachings for bodhisattvas, pratyekabuddha, and śrāvaka (kaie). Here the pre-Lotus sūtras, which are abandoned as expedient by the doctrine of relative subtlety (sōdaimyō), are all included in the ocean of the Lotus Sūtra. Once entering the ocean of the Lotus Sūtra, the pre-Lotus sūtras will no longer be dismissed as expedient. All the sūtras entering the ocean of the Lotus Sūtra take up the one flavor of Namu Myōhō Renge Kyō because of the wonderful merit of the ocean of the Lotus Sūtra. There is no reason why they have to be referred to by other names such as nembutsu, Ritsu, Shingon, or Zen. Consequently, Grand Master T’ien-t’ai said in his Profound Meaning of the Lotus Sūtra, “Just as water becomes salty when it flows into the sea, any wisdom ceases to exist in itself after it is taken in the True Wisdom.” Thus he instructs us that no original names be mentioned.
Shoshū Mondō-shō, Questions and Answers Regarding Other Schools