Principles of Hapkido:
In Hapkido, circular movement is emphasized rather than linear movements. Almost techniques of Hapkido should follow the three principles as follows.
Hwa, (和, the non-resistance) is the act of remaining relaxed and not directly opposing to an opponent's strength. For example, the defender would avoid a direct confrontation by moving in the same direction of assailant's attack and utilizes the opponent's forward momentum for throwing him.
Won, (圓, the circular principle) is a way to gain momentum for executing techniques. If an opponent attacks in linear motion, as in a punch or knife thrust, defender would redirect the opponent's force by leading the attack in a circular pattern, thereby adding the attacker's power to his own.
Yu, (流, the water principle) is the softness and adapability same with the propery of water. Softness is the main property of Hapkido. In Hapkido, the power does not rely on its own physical force alone, much like as water. Defender will attempt to deflect an opponent's strike, in a way that is similar to free-flowing water being divided around a stone only to return and envelop it.