Nichiren, who considered that practice emerged in Mappo (Age of the Final Dharma), thought that the practice of chanting Namu-myoho-renge-kyo should be the main part of practice after he was exiled to Sado Island (Sado Province).
それを末法の時代に生誕したと考えた日蓮は佐渡ヶ島（佐渡国）に流されて以降この「南無妙法蓮華経」と唱える修行を中心にしないと駄目だと考えた。