Furthermore, threefold refers here to the three sutras: "Muryo gikyo" (Sutra of Immeasurable Meanings), "Myoho-renge-kyo" (the Lotus Sutra) and, "Bussetsu Kanfugen bosatsu Gyoho-kyo" (Sutra of Meditation on the Bodhisattva Universal Virtue).
なお、ここでいう三部とは、『無量義経』、『妙法蓮華経』、『仏説観普賢菩薩行法経』の三経を指す。