Karate is a BUDO (Japanese martial art) for which the purpose is not to win against an enemy outside of your body but to win against yourself. That means to win against your fear, doubt, indecisiveness and to be surprised by nothing.

If karate is used as a method of self-defense, it is very powerful. With karate you will be able to finish your enemy with only one blow. (If you cannot finish your enemy with one blow, it means you are studying some mimic of karate or you are a green horn.) Karate can be enjoyed as a sport, but because it is powerful, mistakes can be disastrous. Therefore, he who practices karate must trust his opponent and must be trusted by his opponent. To be trusted by your opponent, you must show respect to your opponent and always demonstrate your tranquility.

People believe that there are limits to the strength of their bodies and minds without really trying hard to overcome the limits. With proper training, the mental and physical barriers can be removed to reveal surprising power. Karate was devised to overcome weaknesses and limitations by bringing out hidden or unnotices potential.
(Copyright 1994, Kioth Karate by S. Sugiyama)