Circular Motion is one of the easier principles to explain. Basically when you are attacked in a straight line, instead of stopping the attack, you redirect it in a circular direction. When applied to self-defense, using a circular release makes it impossible for your opponent to resist. Circular motion also assists in both strikes and throws: with throws, it enables you to throw someone much larger with far smaller force. With strikes (e.g. a spinning kick) it increases the power through the greater distance the strike travels and the circular wind-up or whipping motion.
Non-Resistance is a major characteristic in Hapkido. For example, in defending against a powerfully thrown punch the Hapkidoist would never step inside an opponent’s area of greatest momentum and use a hard block. Instead, the Hapkidoist would avoid a direct confrontation by parrying the punch with a soft circular block; this would divert the opponent’s power and allow you to counter-attack.
Another example is when an opponent grabs your wrist and pulls, instead of resisting by pulling away, a Hapkidoist would go with the opponent’s pull and use this added momentum with a circular release to escape. This also applies if an opponent pushes you, with a move you can divert their energy into a throw.
Water Theory can be broken down into several different aspects. The first is the ability to flow around obstacles, like a stream around a rock; this is reflected in the Hapkidoist moving around an attack. Water dripping onto a rock can find weak points and through constant pressure flow into and through the rock, this shows how a Hapkidoist can attack an opponent and through a weak point enter the opponent’s defense to take control, or to damage. Like the power of a wave crashing onto a beach, so too can a Hapkidoist focus their attack. This is also shown through the power of water when pushed through pressure hose, this concentration can be focused into doing more damage to your opponent.