I am constantly asked by people "What's the best knife for self-defense?"

Not to put too fine of a point on it, but seeking a simplistic answer to a complex issue is going to
  a) Cost you a lot of money
  b) Make someone else a lot of money
  c) Get you raped in prison.

There's a lot of macho advertising, marketing and internet touching yourself when it comes to 'tactical knives,' 'fighting folders,' and combat blades.  This is an extension of the whole 'knife fighting' market and idealizing knife combat that is being pandered by self-proclaimed knife experts. What's worse is they are selling these illegal and dangerous fantasies as -- and I use this term loosely -- self-defense.

Since I do expert witness work in court cases involving knife crimes, homicides and assault with a deadly weapon cases(1), I have a slightly different approach to the subject. Namely:

If you're looking for a knife for self-defense, you're setting yourself up on points A-C

If you go down this road and buy a tactical fighter, a combat ready knife or some wicked looking hooked fighting knife designed by a master knife fighter  ...hopefully you'll only get screwed on points A & B.

A Knife Is A TOOL!
Let's start with this important fact.

Tools do things your hand, fingers and teeth can't. You can't hammer a nail with your fist, you can't cut down a tree with your fingers you can't carve with your teeth. As such, tools allow you to do a variety of jobs and applications. The key word here is variety.

A weapon on the other hand is a modified tool. These modifications make it only good for one thing. In exchange for this specialization, it is useless as a tool. For example, a dagger is a double-edged blade that allows cutting in either direction. This modification removes your ability to put your thumb/finger on the back of the blade ... a critical component in tool use.

Can a tool be used as a weapon? Yes. But the point here is that it is ALWAYS an improvised weapon. As such, it will NEVER be as over-all effective at the task as an item specifically designed as a weapon. Can it still kill? Yes any tool can be abused in this manner. But the design of the tool is not for killing. It lacks the specific modifications necessary to make it a weapon.

Let's put this in plain English. Hanging words like tactical, combat ready, combative, commando, urban warrior or some macho and cool sounding name on a knife will only do two things:
  1) Raise the price
  2) Give the prosecution ammo against you because you were carrying
    a 'fighting knife. (As in if you weren't planning to stab someone why were
    you carrying such a scary and wicked knife?)

So the first standard for choosing a knife is know that you are buying a tool, NOT a weapon. 99.999% of what you are going to be using it for is as a tool. That should dictate your purchasing decision.

Knife vs. Gun
People who are obsessed with 'self-defense' often want to carry knives because they are uncomfortable with carrying a gun. This is like saying "I'm more comfortable with The Plague than Ebola," both will kill.

In the eyes of the law a gun and a knife are both considered lethal force instruments. That means the same rules about when you can legally use them, under what circumstance their use is justified.

Let me state, for the record, you do NOT get the training on when to use a knife, when NOT to use a knife from a martial arts school, knife fighting/Filipino Martial Arts seminar or on the internet. You get this specialized training ONLY through taking courses designed to inform you about the complexities of the subject (e.g. The Armed Citizen's Legal Defense Network)

I cannot stress this idea enough, especially if you are thinking of carrying a knife for 'self-defense.'

One of the things that is important is YOU must know what self-defense really is, NOT what you think it is. Acting on what you think self-defense is while holding an item will get you into deep  trouble.  Weapons are like power tools, mistakes happen faster and when they do, they are bloody.

So if you still are thinking about buying a knife to defend yourself, you need to look into and get training about what is and what ISN'T self-defense (and the most common mistakes people make when it comes to claiming it). That training is MUCH more important than what kind of knife you have.

Armed Society
Another important piece of equipment to have when it comes to carrying a knife for self-defense is this: Miss Manners: A Citizen's Guide To Civility.

Yes, I just sent you a link to a book on etiquette. Not only will it help to keep you from being hassled by the cops for carrying a knife, but it does wonders for keeping you out of conflicts where you'd be tempted to ram a knife into someone's guts. One of my favorite quotes is from Robert Heinlein "An armed society is a polite society. Manners are good when one may have to back up his acts with his life."

Bottom line is anytime you put a knife into your pocket, strap on a gun or take control of an item that can take a human life, then you must also take on a higher level of responsibility. It is no longer about you, it is about the effects your actions have on others. You WILL be held accountable for your actions, especially if you use it on someone.

And a good starting point is manners. Manners as a daily thing, even. Not only do they help you avoid getting into violent situations, but they do wonders for your career and personal relationships.

I just worked a case wouldn't have happened if everyone had been better behaved. And the guy -- even though it was self-defense -- was arrested and charged with murder. (He took a plea bargain for 8 years over killing the guy because he'd done some other stupid stuff that weakened his SD case.)

What a lot of people don't understand when they fixating on getting a weapon for defending themselves is that they are taking on the responsibility of killing someone else. So how does this apply to manners?

Ever wonder where manners came from? Do you believe that good manners is a sign of weakness and vulnerability? If you do, then you are absolutely wrong. In a world where everyone was armed, squabbles often turned deadly and insults turned into duels. Manners are a way for armed people to co-exist without having to kill each other.

And if you are carrying a knife, you have to join that crowd. Not only does your life depend on it, but so too do other people's.

Selecting A Knife
When it comes to buying a knife I always tell people to take their seeing eye dog. Because they are going to go blind.

You're not going to see brand name, maker or manufacturer. You're not going to see shape, coolness, swept lines, wicked points or anything. And the biggest thing you're not going to see is all the 'tactical' bullshit and advertising.

You buy a knife because of how it feels.

Everyone has a different weight, balance and handle preference. Personally I like shorter, thicker blades with the weight in the back and the balance in the handle. My wife prefers longer blades with the weight in the tip. My ex preferred a handle with finger grooves, etc., etc..

The importance of this is because first and foremost a knife is a TOOL! It is not a weapon, it is not for self-defense. It's for doing a job you can't do with your fingers. You're going to be using it for what is 99.999% of the time. As such you need something that feels good in your hand.