Nichiren taught the idea that any unenlightened person kept 'bussho' (the Buddhist nature) in the inside of him and once he performed a Buddhist practice (called 'gyo') of chanting the Nichiren chant 'Nam Myohorenge-kyo' (called 'shodai'), 'bussho' would appear on the outside of him.
日蓮は、いかなる凡夫にも「仏性」が秘められており、「南無妙法蓮華経」（なむ・みょうほうれんげきょう）と題目を唱える「唱題」の行(仏教)を行えば「仏性」が顕現するという思想を説いた。