In taekkyon the hands move constantly in a circular motion. Repetedly changing direction to suit the situation.
The circular movemnets of the hands help to parry, by diffusing strikes and kicks, as well as trapping an opponent’s arm or leg.
In this instance of trapping arms and legs, it is easy to apply joint locks. Thus, the rotating of the arms as in taekkyon is important. And for this reason, practitioners of Hapkido would benifit greatly from learning this rotating arm technique.
As the arms constantly move in circles, and are constantly changing direction, they are adaptive to changing situations. And it is not difficult to change from parrying(defense) to striking(offence).
The hands/ arms move to a rhythm. This rhythm used is irregular, slowing and speeding up. It is usually a 3 beat but changes to a 1, 2, or 4 beat are common.