In accordance with the division of the Hoke-kyō into Shakumon and hommon, the Nichiren Sect distinguishes two lines of transmission of the teaching, external and internal. The external transmission is the line of teachers in India, China and Japan who expounded the doctrine of the Lotus Sūtra. These are:

• Śākyamuni Buddha and Yakuō Bosatsu (Medicine King) from India
• Tendai Daishi from China
• Dengyō Daishi and Nichiren Dai Bosatsu from Japan

The internal transmission is the line of those who understood the truth of the Original Doctrine or hommon. These are Śākyamuni Buddha, Jogyō Bosatsu, Nichiren Dai-Bosatsu. …

Jōgyō Bosatsu (Viśiṣṭacāritra Bodhisattva), with his innumerable followers issued from the gaps of the earth, appears prominently in Chapter XV and XXI and is ordered by Śākyamuni in preference to all other Bodhisattvas, to propagate after his decease the most perfect teaching. Therefore, Nichiren not only regards Jōgyō Bosatsu as the proper transmitter of the hommon of the Hoke-kyō, but considers himself as a reincarnation of the Bodhisattva. Nichiren found his life in perfect harmony with Śākyamuni’s prophecy that Jōgyō Bosatsu would reappear and propagate the hommon teaching in the Mappō time.

It is clear from this that though the outer form of the doctrine depends on the Tendai School, the internal transmission, considered more correct, is entirely independent of any other doctrine.