In the Zen sect, the teacher priest would give his own portrait to his pupil monk as part of the inka (certification of spiritual achievement), and so, as the Zen sect became popular, many chinzo were depicted.
師に当たる僧が弟子の僧侶に対して、印可の一部として自賛の肖像を与えるところから、禅宗の普及と共に多く描かれた。