In Chan Buddhism, koans (gong’an) function as living “cases” that disrupt ordinary patterns of thought and point directly to awakening. They originate in recorded encounters—brief, often puzzling exchanges between early Chan masters and students—where conventional logic seems to break down and a more immediate understanding is demanded. Rather than being treated as doctrines to be explained, these stories and sayings are used as practical tools to unsettle fixed views and reveal a reality that is not confined by conceptual categories. Collections such as the Blue Cliff Record and the Gateless Gate preserve such cases and are used as training materials, but always as prompts for realization rather than as objects of mere study.

Within meditation, especially in lineages associated with Linji, practitioners often work not with an entire story but with a huatou, a short phrase or “word-head” drawn from a koan. Phrases like “Who is dragging this corpse around?” or “What is your original face before your parents were born?” are taken up in seated practice and daily activity as focal points for sustained inquiry. The purpose is not to arrive at a clever solution, but to cultivate a “great questioning” that exhausts the discursive, analytical mind. As attention returns again and again to the huatou, habitual conceptual tracks are worn out, and the possibility opens for a direct, non-dual experience that Chan texts describe as awakening.

Koans also shape the intimate relationship between teacher and student. A master assigns a koan or huatou according to the student’s capacity and stage of practice, then tests the student’s understanding in interview or more dynamic exchanges. Responses are not judged by their intellectual sophistication, but by whether they manifest insight in tone, timing, and conduct. Successive koans may be given to deepen and refine an initial breakthrough, ensuring that realization is not a fleeting experience but something that functions clearly in varied circumstances. In this way, koan practice serves both as a catalyst for awakening and as a rigorous means of verifying and maturing that awakening within the Chan tradition.