It is preached in the “Medicine King Bodhisattva” chapter of the Lotus Sūtra, fascicle 7: “Moon Deity is the foremost among the stars. The same is true of the Lotus Sūtra. Of the countless number of Buddhist sūtras, this sūtra is the most illuminating.” This scriptural statement means: “Stars in the sky shine either one-half of a ri (about 5 km), eight ri, or 16 ri in all directions. On the contrary the full moon in the sky shines 800 ri all around. For instance, the Flower Garland Sūtra (60 fascicles in the old translation or 80 fascicles in the new translation), the Wisdom Sūtra (600 fascicles), Hōdō sūtras (60 fascicles), the Nirvana Sūtra (40 or 36 fascicles), and innumerable other sūtras such as the Great Sun Buddha Sūtra, the Diamond Peak Sūtra, the Sūtra on the Act of Perfection, the Sūtra of Meditation on the Buddha of Infinite Life, and the Amitābha Sūtra are like stars, while the Lotus Sūtra is like the full moon.” This is not what was preached by Bodhisattvas Nāgārjuna and commentators in India, or Grand Master T’ien-t’ai and Tripiṭaka Master Śubhākarasiṃha who preached Buddhism in China. These are the golden words of Lord Preacher Śākyamuni Buddha, which are like the words of the Son of Heaven.

Matsuno-dono Goshōsoku, Letter to Lord Matsuno, Writings of Nichiren Shōnin, Volume 7, Followers II, Page 65