In the Zen sect, a disciple who was acknowledged as having attained enlightenment had his master's portrait drawn by a painter; the master then wrote his preaching on the portrait based on the style of Chinese poetry called "gemon", and this portrait was used as a kind of diploma.
禅宗では、悟りを開いたと認められた弟子の僧侶が、師の肖像を絵師に描いてもらい、師はその肖像の上に「偈文」という漢詩の形を取った説法をしたため、これを一種の卒業証書とした。