Is this truly an Oriental Massage Technique? I'm actually not sure, but it certainly seems like something you would see in a James Bond movie.
Hacking works on many areas of the body (back, back of the legs, thighs). The technique involves keeping the first three fingers of the hand together. The fourth (pinkie) finger hands downward and partially absorbs the blow.
Executed properly this technique makes a rhythmic sound that is itself relaxing.