koan

A riddle-like puzzle used for teaching in Zen Buddhism. It cannot be solved by reason, but instead forces the student to solve it through a flash of insight. A well-known example is the question, "What is the sound of one hand clapping?" For a collection of koans, click here.

A seemingly paradoxical riddle or statement that is used as a training device in Zen practice to force the mind to abandon logic and dualistic thought.