Isshin-Ryu Vertical Snap Punch: 

The vertical snap punch has the advantage of not exposing the ribs to attack since the elbow covers this area. It also removes exposure of the elbow to joint manipulation, unlike the traditional twist punch since the forearm doesn’t rotate. It is quicker and is an example of the application of economy of motion.

When seeing this technique performed in kata, it can be a disguised grab. The chambered hand on the obi is pulling the opponent’s trapped hand the karateka’s waist to increase the impact of the punch.

The chambered hand can also be a grab to pull the attacker into the punch. This strike is made off the lead leg and is akin to a boxer’s jab, but it has more power behind the blow than a typical boxing jab. In personal combat the lead hand vertical snap punch is more of a distraction to set-up another more powerful attack. The punch can also be delivered off the back leg. To increase power you simply add hip and shoulder rotation coupled with weight transfer from the back leg to the front

When Shimabuku sensei was being trained by Kyan Chotoku sensei, he was not taught to rotate the fist horizontally but to keep it on an angle. This angle is the same as the curvature of the rib cage. This position allows for deeper penetration of the xiphoid process. The problem here is this, even though it is very effective at stopping a confrontation, it can slowly kill the adversary if a portion of the xiphoid process is broken off and cuts the diaphragm. If you want to see the original fist position watch Simabukuro Zenpo sensei demonstrate Seibukan karate. He performs the kata exactly as taught by Kyan sensei. Somewhere along the way the Isshin-ryu fist became more vertical. This is a common error made by students today. The fist should be angled slightly.

Stance:

• Seisan Dachi.

Note: Seisan-dachi is a forward walking stance and is both a fighting position and a transitional position.

Execution:

• Lead hand goes forwards while rear hand is pulled to the obi (belt).
• Shoulders rotate and hips rotate.
• Weight is transferred from the rear leg to the front leg, but not as much because this is a speed technique and not a power technique. Most of the power in this punch is created by speed.
• Once the punch is extended it is quickly pulled back about two inches.

Note: This was explained as striking the opponent twice. The first impact pushed into the attacker’s solar plexus and the quick pull back allows the solar plexus to snap back into place. One prominent martial artist called the effect striking with a hammer and then hitting the opponent with a chin whip.

• Rear hand is placed on the obi (belt) signifying a trapping of the opponent.

Note: If you trap an arm, that weapon is tied-up. If you grasp the obi or belt the adversary cannot get out of your circle of combat. Some believe that placing the fist on the obi is a blocking motion of the opponent’s strike.

Striking Part of the Hand:

• The striking part of the fist is the first two knuckles of the hand.

Target Area:

• High: Chin
• Middle: Solar Plexus (Most Common)
• Low: Bladder