Zen in its essence is the art of seeing into the nature of one’s own being, and it points the way from bondage to freedom. By making us drink right from the fountain of life, it liberates us from all the yokes under which we finite beings are usually suffering in this world. We can say that Zen liberates all the energies properly and naturally stored in each of us, which are in ordinary circumstances cramped and distorted so that they find no adequate channel for activity. This volume being second in the series, stresses on the study of ‘The Koan Exercise’, which at present constitutes almost the alpha and omega of Zen discipline, especially as it is practised in the Rinzai School of the Zen sect. The Koan technique is full of pitfalls, but its development was inevitable, and without it Zen might have not survived. The study of the Koan exercise as presented in this series is a general idea of what it is.