A "hwadu" is a type of koan used in Zen Buddhism to aid in meditation and self-inquiry. It typically consists of a short phrase or question that challenges the practitioner to go beyond logical thinking and engage in deeper contemplation. The purpose of a hwadu is to provoke a direct experience of enlightenment. Practitioners often focus on a hwadu during meditation, repeating it mentally to uncover its meaning. This process encourages a shift in perception, helping individuals break free from conventional thought patterns. Ultimately, hwadu serves as a tool for spiritual awakening and insight into the nature of reality.