John Daido Loori

“The koan is simply a tool, an aid to self-inquiry and realization that, as Daido Roshi points out, must be supported by the personal foundation one brings to the practice: great doubt, great faith, and great determination. Without, in particular, great doubt (the drive to resolve the question of life and death), the student can easily mistake koans as the goal of Zen practice, rather than as a means to that goal.” (Sitting with Koans)