My style is Wado Kai, which is a defensive 'no contact' form of karate. 'No contact' is actually more difficult than 'full contact'.
I've learned to recognize trouble from miles away, and how to avoid it. But if in doubt, knock 'm out.
And always strike first.
Knee caps, or in the worst possible scenario, the eyes.
I've used my skills once, and I must admit, it's the best adrinaline rush I've ever felt.
Peace!