I think we’ve all seen or heard people advise folks that you should always carry a defensive knife that’s razor sharp and never use it as your EDC knife for opening boxes, etc. I just don’t buy it.
First off, there’s a simple issue of carrying one more thing. I already carry my gun, keys, phone, and multi-tool on my belt. Add to that all the crap I carry in my pockets, and I really don’t have much space for another knife. Of course, this is personal preference, and I’m currently carrying 5 knives between the lock blades, multi-tools, etc that I normally carry.
The major argument for a dedicated defensive knife is that you need to keep it as sharp as possible. First off, this suggests that it’s ok to let your EDC knife become dull. It’s easy enough to keep your EDC knife sharp. Most of the time, all it really needs is an occasional session with a leather strop to stay damn sharp.
There’s also the fact a knife just doesn’t need to be that sharp to cut you. Sure, a razor sharp knife is easier to cut flesh, but humans have been chopping each other up for millennia. It was fairly common for soldiers to use whatever rock they found to vaguely sharpen their weapons back in the sword and shield days. And that was with iron and steel, much less bronze or chipped stone.
Heck, I’ve seen folks argue that it’s actually better to use a duller knife as a weapon. If you’ve ever been cut with a really sharp knife, you may remember never feeling the cut. The idea is that a duller knife with tear at the skin more and make your attacker really feel it. I know some folks that advocate the use of a serrated knife for this reason over a straight edge.
My last big thing is that you should know your knife. One thing that’s hammered into your head in any martial art is that your weapon should be an extension of you. It would make sense that the knife that you use every day for common tasks would become that way. This isn’t necessarily true with a dedicated defensive knife. Especially if the blade profile is significantly different for that EDC. Something like a karambit requires serious training to become proficient in for that reason.
Am I saying that you shouldn’t carry a dedicated defensive blade and you’re stupid if you do? No. What I am saying is that, if you do, you might want to re-evaluate why you’re carrying it. Maybe you’ll decide that you really don’t need to. If you do decide to continue to do so, find someplace to get training.