Never Attack Where the Opponent is Strong
Never attack an opponent where he is strong, only attack where he is weak. This is a universal concept used by internal and external martial artists alike. It is also common sense for people who have never trained a martial art. Trained martial artists each use it in their comfort zone, and at the distance they train to fight at. I have however seen some forget this concept when they are fighting at a different range then they normally train for. To me that means a deeper understanding of the concept is needed.
For example taijiquan practitioners spend a lot of time training push hands. They use this practice to develop lightness and sensitivity. Whether practicing single hand, double hand, fixed pattern, or free style, they always start with the gap closed and they are already touching.
When doing push hands two people face each other and make contact feeling their opponent. One will initiate movement, normally seeking the opponents center. The defender will yield and deflect the attack. If the attacker puts to much tension/ power in the attack or over extends, he makes himself vulnerable to counter attack. If the defender stiffens using strength to defend they will expose a weakness the attacker can exploit. They push back and forth looking for this opening. Sometimes in order to create this opening one might tense push or pull a little hard momentarily at a point to get the other person to commit his weight and strength to defend that attack. The side they are strong on is the full side, their opposite side goes empty to balance the full side. The empty side is weak. Attacking their empty side gets the best results.
When you ask most taiji practitioners how they close the gap to touch their opponent in a fight, the most common answer is that you creep in until you can touch them. I’ve heard some say you just have to be willing to take a shot to close the gap if necessary. I’ve also heard this same thought process from Judoka, Juijitsuka, and wrestlers. To me that means they don’t understand how someone that is primarily a striker would apply the same concept.
When opponents square off, they will have some form of on-guard position that puts their strongest defense and offensive tools toward the opponent. Unless you are much bigger, stronger, and faster then the opponent it would be unwise to attack them head on at their strongest point. They also start outside of each others reach, and must close the gap to strike in a real fight. When you are in transition/moving into the range where you can hit each other you are vulnerable to counter attack.
To attack the opponent when and where they are weak external martial artist move around their opponent toward a weak side. The opponent has to adjust to bring his strong side back to facing his opponent. They will have a full side as they move making the other empty. Anytime they are in transition they are weak as well. They use different footwork, feints, fakes, broken rhythm attacks, etc. to set up an opening to attack the weak/empty side. If you can see how they are breathing at the end of their exhale they are empty and weak. They have to inhale and become full before they can move and defend. Time your attack to coincide with the end of the exhale. These methods are how they will close the gap.
Once the gap is closed and the first strike has hit, their mind goes to where they were attacked, leaving other targets empty and easy to attack. That is way you work up and down the body. That is why you work the various combination. You always want to be attacking the empty weak side.
Strikers that specialize in fighting at a distance need to be careful if they end up in a clinch, they don’t forget the same concepts they use at a distance. They then need that same understanding that people trained in Taiji, Judo, Jujitsu, and wrestling have of this idea.