There are ten similes preached in the “Medicine King Bodhisattva” chapter, the first of which is the simile of a great ocean. Let me speak of this simile. In the continent of Jambudvīpa, where we human beings live, there are 2,500 rivers. In the continent of Aparagodānīya there exists 5,000 rivers. Altogether 25,900 rivers flow in the four continents lying in the four directions from Mt. Sumeru. Some of these rivers are as long as 100 or 250 miles. Others are as short as 25 miles, 100 yards, or six feet. None of these rivers, however, can compare to an ocean in depth.

Likewise, the Lotus Sūtra is supreme among all the sūtras—all the sūtras expounded before the Lotus Sūtra such as the Flower Garland Sūtra, the Āgama sūtras, the Hōdō sūtras, the Wisdom Sūtra, the Revealing the Profound and Secret Sūtra, the Amitābha Sūtra, the Nirvana Sūtra, the Great Sun Buddha Sūtra, the Diamond Peak Sūtra, the Sūtra on the Act of Perfection, and the Sūtra of Mystic Glorification—all the sūtras preached by Śākyamuni Buddha, the Great Sun Buddha, the Buddha of Infinite Life, Medicine Master Buddha as well as all the sūtras preached by all the Buddhas in the past, present and future.

Yakuō-bon Tokui-shō, The Essence of the “Medicine King Bodhisattva” Chapter, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 28