Harmony is the most important element one should achieve in Hap Ki Do training. The Hap Ki Do students' harmony must manifest itself by uniting the mind, body, spirit, techniques, and environment. Harmony is the most important element one should strive to achieve through their training. We practice what we are shown countless times so that our body and mind will eventually act as one unit in response to a confrontation.
But when faced with an attack, the true Hap Ki Do practitioner reacts by instinct, not through conscious thought. If one must think about how to react, it is too late. Therefore, we practice our techniques repeatedly. Merely knowing how to use a technique is not good enough. The Hap Ki Do student should not only memorize the techniques, but the student's harmony should be Reflexive, Second Nature, or Action without Thought.
After one achieves harmony within oneself, the next requirement is to harmonize with one's opponent. Having accomplished this, the Hap Ki Do student will find it quite easy to control the movements and energy of an opponent. The words “non-resistance" are often substituted for harmony in defining the theory. Before an attack can be directed in a circular manner, it must first be received or intercepted with a non-direct block or maneuver, thus allowing a harmony to be created using the opponent's oncoming force to fuel the defending motion.