The koan system is a unique and traditional teaching method of Zen Buddhism. It is emphasised most within the Rinzai lineage but is also used in the Soto school. A koan derives from actual encounters, usually (but not always) between accomplished Zen masters and their students. Successive generations of teachers have related these encounters to their students to illustrate particular principles of Zen. Questions or problems, often paradoxical, highlighted by each story were presented to encourage and test them in their training. Over time the encounters and their associated problems were formalized and systemized into koan collections like the Mumonkan, the Hekiganroku and the Shoyoroku.
The koan system enables the Zen teacher to test the individual student’s understanding of Zen, not intellectually, but as it applies to the student’s own life. It is a form of practice that requires the supervision of a recognised teacher who has himself or herself gone through this rigorous training. Keizan Sensei is authorised to supervise koan practice, and holds daisan (interviews) both on a weekly basis in Liverpool and on sesshin (intensive retreats).