I'm a pretty big guy, so generally I don't have to actually defend myself all that often. Most people see 6'2" 200+lb. bushy eyebrows and ponytail and walk wide around. If I do see someone approaching, looking a bit too eager, I just start reaching for my knife. Generally they catch the hint and turn away by the time I've made eye contact. (Don't have a CCW permit yet. They're rather pricy here and I'm still working on getting one.) However once about 12 years ago I did actually have to back it up. I had the odd misfortune of picking that one day to not have a knife on me, and two redneck little punks thought they had something to prove. One pulls a knife, and I'd like to say that had he not, it would just be one more brawl, but when you bring a weapon in, I get MEAN. Thankfully a little combination of martial arts, and good old American fighting dirty dispatched them. I kick knifeboy right straight in the family jewels, twist the knife out of his hand and throw it away, give him a good elbow in the spleen, a chop to the throat, hip toss him on the ground and stomp a few mudholes in him for good measure before his buddy knows what's happening. The knifeless buddy turned out to be a bit quicker, forcing me to lock him up. Eventually after he breaks out of a chokehold I finally get him on the ground in a full nelson with my knees pinned against his back, leaving him pretty much helpless. As there were no phones, and no one around, I really didn't see a way of getting out of it. Thankfully he started begging, and at the time being a bit more softhearted than I am today, agreed to let him go. Redneck troublemakers beat a hasty retreat, I straighten my shirt and calmly continue on my way. I haven't really had to dirty my knuckles since. Most BGs just don't target a guy like me. Doesn't mean I don't keep my eyes open. Though It's amazing just how many of our stories involve bad guys picking the wrong person to pull a knife on.