According to 'Kanzeon Bosatsu Fumon Hon No. 25' of the Hoke-kyo (Kannon-gyo) sutra, in order to provide relief to all people, Kanzeon Bosatsu adopts one of 33 different appearances to meet the needs of the particular person; these appearances include 'Busshin,' 'Shomonshin,' and 'Bonnoshin' (as below).
法華経「観世音菩薩普門品第二十五」（観音経）には、観世音菩薩はあまねく衆生を救うために相手に応じて「仏身」「声聞（しょうもん）身」「梵王身」など、33の姿に変身すると説かれている（下記の通り）。