Karate kata contain many movements that travel in opposite directions. Although it is quite simple, this concept of opposing forces is one of the signature methods of Okinawan karate. It can be seen in kihon practice, as well as in advanced kata, because it is extremely versatile. In application, this concept can defend, attack, clear obstructions, dislocate joints, and increase the power of strikes.
I have discussed the application of hikite while punching in the past. This is the most common example of opposing forces that can be seen in karate. As the strike extends, the other hand retracts, pulling the opponent into the strike, increasing its power. When I teach this, I use the analogy of a car crash. A punch hitting a stationary target is like a car hitting a wall. A punch hitting a target moving toward it is like a head-on collision between two cars. As bad as as the former may be, the latter is worse because of the combined energy of two opposing forces.
A variation of hikite can be seen in the osae-uke (pressing receiver) found in kata like Naihanchi, Passai, Kusanku, and Gojushiho. This technique utilizes a shorter pull, and either pulls down while a strike rises, like the example, above, or pulls in while a strike extends. This serves much the same purpose as the hikite used when punching in kihon practice–increasing the power of a strike. Generally, the pulling hand grabs and controls an arm, which can reduce the opponent’s ability to defend against the strike. However, there is no rule stating that the pulling hand can only be pulling an arm. The same concepts can be applied while grabbing a leg, the head, a shoulder, or a piece of clothing.
There are also opposing movements that separate, rather than come together. This can be seen in the morote-gedan-barai (double low sweep) of Seiyunchin, or the parting hands of Passai and Kusanku. These movements can, of course, be useful for clearing away the opponent’s arms, whether they are attacking, or held in a defensive position. They can also be used much like hikite, in order to pull the opponent into a strike, although the striking method clearly differs from the standard application of hikite. There is also no restriction against applying this method to parts of the body aside from the arms.
Movements where the arms cross can also be seen as opposing forces, whether the arms are crossing together like Pinan Shodan and Kusanku Dai, or crossing and parting like Naihanchi and Passai. These movements are very useful for passing and controlling limbs, whether they are attacking or defending. This makes them very effective for applying tuidi-waza (seizing hand techniques), and also has the benefit of being able to pull an opponent into a strike. Just as with the previous examples, however, one need not limit themselves to the arms when applying these methods. The concept is the same, regardless of the specific application.