A Capping Phrase(着語/箸語jakugo), or 下語(agyo) of a kōan is a proof of solution of the case riddle, but not the solution itself. In Zen Buddhism, kōan is used both as a meditation device and as an expression of Enlightenment(悟り/覚りsatori) – a radical experiential insight into the nature of things and the self alike. A capping phrase is supposedly an articulation of such enlightening experience, most of the time in verse.