“Kung-an [koans] were in vogue during the Tang Dynasty. Each Zen practitioner had a kung-an to work on. But before this period, Zen Masters did not need kung-an. The kung-an is, therefore, not something absolutely indispensable to the practice of Zen. It is, more or less, a skillful means created by Zen Masters in order to help people who work under their direction.” KoansSkillful Means Book:Zen Keys: A Guide to Zen Practice Source: Zen Keys: A Guide to Zen Practice