The good fighters of old first put themselves beyond the possibility of defeat, and then waited for an opportunity of defeating the enemy. – Master Sun Tzu, Art of War
In the classic Chinese strategy guide The Art of War, Master Sun explains that we control our own defense, but the opportunity for offense is provided by our opponent. We cannot force our opponent to make a mistake, and we cannot force a move on an opponent who is properly defending against it.
In order to achieve victory in a Jiu-Jitsu match, the first thing is to survive. Survival requires defensive mastery. A skilled opponent will seize on any defensive mistakes and use those opportunities to defeat us.
One aspect of defense is in knowing the strengths of your enemy, and avoiding them. If your opponent is strong then don’t engage in a contest of strength, if your opponent is quick then don’t try to speed past him, if your opponent has a great top game then don’t pull guard. If he is large and you are small he will try and overpower you so you must stay out from under the power. If you are large and he is small he will try to attack from the edges and you must defend against it.
Another aspect of defense is in not moving without a plan. If you thrash around without understanding where you are, or what opportunities you are providing for your opponent, you are ensuring a quick defeat. You are using up precious energy to go from a position that may be bad to another that might be even worse. First stop and observe where you are, next make a plan for getting to a better place, and finally execute the plan in a deliberate way, without using unnecessary amounts of energy.
Perhaps the most important and least understood part defense is inner calm. If your body is rigid and tight, it is easy for your opponent to manipulate and move it about. The same is true of your mind. Rigidity and panic are like a fogs and impair your judgement. Relax and accept the position you find yourself in. Observe the situation closely as an bystander would see it. You might find that the choke you were so fearful of isn’t applied correctly and that if you relax you can wait it out. Or you may see an opportunity to improve your position that you didn’t notice while you were panicking.
The most skillful fighters don’t seem to fight at all; their victory was decided before the match began. They have a full mastery of defense and so their opponent continues to move from one mistake to the next and it is the master’s choice when to attack and finish the fight. The master was never in any danger or uncertain about the eventual outcome.
Jiu-Jitsu has been described as kinetic chess, and it is a good analogy. You must move to advance your position, yet each movement is an opportunity for error and a possible opening for your opponent. A skillful fighter can create positions that are very secure and defensive yet allow for attacking the mistakes of his opponent.
If you can master defense, even the most skilled opponent cannot defeat you, but if you only know offense, you will lose every match against a skilled opponent.

- Bill Thomas