How?
- Have your partner stand in a left front stance (zenkutsu dachi) and set up for a right-hand reverse punch (gyaku zuki). Let him demonstrate the punch a few times to get all of his basic principles flowing, until he can lash out with the shockingly powerful punch that Shotokans take such pride in.
Now take hold of his left hand and set up the kanoha gaeshi (te nage) wrist lock. Apply just enough pressure to tip him about one inch to his left. You can see his spine go out of alignment. At that point you have broken his posture, and without posture you have broken his karate. Let him try to punch, but hang on to his hand. As he pulls the hand back toward his hip (hiki te) the wristlock becomes much more painful, and his posture suffers even more dramatically. This just ruins the reverse punch. It has the same effect on the front kick (mae geri). Most people can't even complete the extension of the technique. They stop dead halfway there.
The counter to this lock is in the kata Kanku Dai, but odds are that the senpai doesn't know that. In traditional karate, the senseis don't explain that move. (This is step 50 in Shojiro Sugiyama's 25 Shoto-Kan Kata.)
I've done this demonstration successfully many times, but once it went seriously wrong. I had a grizzled old street fighter who prided himself on "powering through" any pain to reach his opponent. He said no wristlock would stop him from kicking me. I set the wristlock, and he attempted to kick.
He was tough. He proved that he could reach me with the kick. He also dislocated the bones in his wrist and had to wear a splint for several weeks. Who won that contest? I'm not sure, but I can tell you this: the sensation of a wrist coming apart under your hands is hideous.
The karate of Matsumura and Itosu was about 80% grappling and only 20% striking. Modern karate classes teach only one-fifth of the historical art. That's fine for "sport" karate, but for self-defense you need the other 80% of the art. It isn't enough to dance around the floor doing katas. It isn't enough to play fist-tag for points against a single opponent. You need to go hands-on with multiple simultaneous enemies to learn self-defense, and traditional karate just doesn't teach that. Not anymore.
This is why experts in "karate jutsu" are springing up around the world. Karate that includes jujutsu is far more effective than is either art without the other.
