Martial Analysis: The Knife

Knives are brutally effective at killing people and terribly ineffective for self-defence. To understand this conundrum, we need to understand the properties of a knife.

First, the pros. Knives puncture and sever. With a properly sharpened knife, it doesn’t take a lot of force to penetrate flesh and open veins. Smaller knives can be easily concealed on your person, under a thin layer of clothing. The blade of a knife adds a few inches to your reach when held in a forward grip; held in the reverse grip, the blade can be used to hook and clear the opponent’s limbs. As a short and light weapon, it can be used freely in the clinch and at grappling range, allowing for multiple rapid strikes. Many commercial knife designs are adequately sharp, cheap and utterly disposable — which lend themselves to specific applications by certain professions.

Now the cons. Knives do not usually impart kinetic energy into a target. They cannot break bones or shock the nervous system; when the adrenaline is going, the opponent won’t know he’s been cut. Most modern knives have little mass behind them, so unlike their larger classical cousins they cannot cut off limbs. Cutting a threat will spray blood all over you. A blade offers only a few inches of extra reach — against a longer weapon like a stick or a chair, a knife wielder is at a clear disadvantage. Folding knives require greater fine motor manipulation — and training — to properly deploy, and there’s a not insignificant risk of messing up the deployment under pressure. Fixed knives, while easier to draw, are harder to conceal. And in the First World, it can be a tad inconvenient if the police ask you why you’re carrying a blade — especially if you do not live in a blade culture.

Forget what you see in Hollywood and most pop fiction: a single lethal strike is not enough. There is no such thing as an immediate kill with a knife. It takes between one to two minutes (usually on the longer side) for someone to bleed to death from a single severed major blood vessel. Up to an hour if you’re unlucky.

In combat every minute is an eternity. If you can’t intimidate the threat after pulling the knife, things will get very ugly, very quick. On the other hand, knives are ubiquitous, cheap, disposable, easy to handle and easy to conceal. Sneaking up on someone and stabbing him to death is depressingly easy. It’s not a clean death: it’s hard and messy and noisy — and that’s if everything goes your way.

This is the reality of the knife. It is an excellent offensive weapon. If you have the initiative, you can overcome its drawbacks through stealth and violence of action, filleting your target without ever giving him a chance to retaliate. And when you’re done if you have a cheap blade, you can simply toss it and get a new one. On the other hand, knives are poor defensiveweapons: they’re not going to quickly stop a threat — at least, not without proper training.

Before You Take Up the Blade

I am not a self-defence instructor. I’ve studied martial arts for a mere three years. Do not count on my words as gospel; if you want to dive deeper, seek out the knowledge of qualified teachers, many of whom I will link to at the end of this post. All I will do here is summarise what I have learned over the years.

In a court of law, a knife is a deadly force implement. It is illegal to use one if your life is not at risk. In many places, it is illegal to use one, period. In my own country, it is illegal for civilians to carry weapons for self-defence. If you choose to carry a knife as a weapon, you must understand your local law and the penalties for breaking it.

If you do carry a knife for the express purpose of combat, you must be psychologically prepared.

Extend your arm to the fullest. This plus the length of the blade is the maximum range of knife combat. More often than not, it will take place closer than that, so close you can smell the threat’s breath. You will be pumped full of adrenaline, your senses will be simultaneously sharper and duller than usual. Through the blade you will feel flesh parting and blood gushing. You will hear the grunts and screams and cries of a dying man. The stench of his fear and blood and waste will fill your nostrils. He will thrash and buck and flail and fight and you have to hold on. You must stitch the threat over and over and over and over again, working the target until the moments a viciously violent living being becomes an inanimate lump of meat and bone.

When it’s over, you will be covered in blood and filth. If the threat had a bloodborne disease, you’ve just exposed yourself. If you’re lucky, you will merely suffer long, agonizing weeks of pain, fever and vomiting. If not, you will suffer long, agonizing months of pain, fever, vomiting, intensive medical treatment — and then you will die. HIV and Hepatitis B and C are the primary pathogens of concern; using a knife on a threat with one is a fine way to catch it.

And even if you manage to walk away clean, you will never, ever, forget. All you can do is make peace with what you’ve done. Be ready.

Targets and Tactics

Different knife arts have different targeting methodology. In Pekiti Tirsia Kali, there are three primary targets: the guts (or groin), the underarm and the throat. There are five secondary targets: the eyes, the hands, the inner forearm, the biceps and the thigh. The primary targets are for killing, the secondary targets are for degrading the threat’s ability to fight.

To defeat a threat with a knife, you must achieve at least one of the following:

  • Psychological stop: Intimidate the threat into running away, or to give you enough space to deploy another option
  • Exsanguination: Puncture so many holes in the threat he bleeds out
  • Structural stop: Sever the muscles, nerves and/or tendons that allow him to move

A psychological stop is simple. When a threat accosts you, pull out a great big knife with a great big smile. If the threat persists, cut at his hands, eyes or face. Humans are hardwired to instinctively protect the head. The flickering blade, the spray of blood and (hopefully) a sudden pain combine to terrify the threat. The idea is to give him something else to think about and to convince him that you aren’t an easy mark.

But this only works against an uncommitted attacker. This is for the mugger, the woofer, the punk with more mouth than brains. Against someone whose blood is up and hell-bent on killing you, you can’t count on it. He may not even register the blade’s existence. Also, in many jurisdictions, this is a crime. You clearly didn’t feel threatened enough to carve up the threat, so it clearly wasn’t a life or death situation, so clearly the use of a lethal weapon is not justified. Use this tactic at your own risk.

Exsanguination is easy. Puncture the major blood bearing organs, sever the arteries and wait for him to bleed out. It doesn’t take a lot of training to do this; you just need to will to do the ugly, dirty job of manslaughter.

In PTK, the throat is the ideal target. Here are the carotid arteries and the trachea. Slice these and blood will gush free and flow into the airways. The threat bleeds and chokes out simultaneously.

After the throat is the underarm. The rib cage protects the chest, but the armpit is undefended. A stab here will puncture the lung and, with a long enough blade, the heart. When you retract the blade, the muscle and tissue collapses. The target suffers a sharp shock to the chest. With every breath, his lung deflates.

The groin region should properly include the guts as well. Here is a wealth of blood vessels and organs: the intestines, liver, spleen, stomach, pancreas. Rapid, upward thrusts and swift horizontal cuts to the region leads to massive internal damage.

Pulling off an exsanguination stop is depressingly easy. Just watch this:

There is no dancing around, no fancy footwork, no posturing. Just four easy steps.

Get as close as you dare. Jam his primary arm. Crash him into a wall or floor. Stab until you or he blacks out.

What if the bad guy attacks you with a blade or stick ? Simple. Cut or stab the hand, clear it out of the way, then bum-rush the target and stitch him up until you or he blacks out. If you have a knife in the reverse grip, it is easier to hook and shear the enemy’s weapon away.

What if the threat is already grappling you? Draw knife, cut him until he lets go, then escape or use the above tactic.

This is the essence of knife ‘fighting’. It is less a two-way exchange of blows, more a sudden furious desperate blitz of steel and spit. Advanced knife tactics are all about creating an opportunity to close in so you can do this.

As discussed earlier, an exsanguination stop will take time. Long minutes of stabbing and slashing and cutting and piercing until the threat ceases to be one. And if he is in knife range, you are also in knife range. The threat may access hidden weapons and fight back even as you stab him. You won’t feel it until you grow weak and black out and die. Even as you work him over, you must deny him the ability to kill you. You need to move as he moves, keeping his arms tied up and jammed against obstacles, and if you sense him drawing a weapon you must respond. Similarly, if the threat has friends, you cannot let yourself be tied up taking one guy out. Otherwise, they will pull you off him and do unto you what you were doing unto him.

The structural stop is based on the concept of defanging the snake. If a threat cannot hold a weapon or cannot stand he is no longer a threat. This plays into the main strength of a blade, allowing you to rapidly incapacitate a threat without the inconvenience of waiting for him to bleed out. As a bonus, you are less likely to take a spray of blood to the face.

The weapon arm is the primary target. The inner forearm is rich with nerves that control the hand. The largest muscles that power the arm are on the upper arm. To attack the former, you need to perform what is known as a gunting or crossada: a scissoring motion that deflects the weapon hand with your secondary hand while simultaneously slashing with your primary. This requires a great deal of training: it is very easy to miss or, worse, catch the blade with your naked hand. Alternatively, you move to the inside of an incoming attack, blocking the weapon arm with your secondary arm and slashing the forearm. To take the biceps or triceps, go for a deep gunting or inside slash, or slip out and jam the opponent’s arm against his body and slash the exposed muscle.

The eye is a valuable target. If the threat can’t see he can’t fight. The goal is to thrust and run. After you stick the eye, the threat will be blind in that eye. Run past his blind spot. This should buy you enough time to flee the area.

The thigh is the other main target. Here, you target the quadriceps. If the threat can’t stand, he can’t slash or strike you. However, if the threat has a firearm, you must also disable the hand (or stomp him in the face) or risk being shot in the back.

While a structural stop may be quicker than bleeding out a threat, it requires training. You need to meet an incoming attack with your naked hand and a tiny blade without getting cut. This requires exquisite timing and bravery, developed only in the training ground. If your cuts don’t go deep enough, the threat will still be active, allowing him to harm you. Further, most FMAs were born in a time and place without heavy jackets or jeans — blades may simply slide off clothing or won’t go deep enough. You need to train the comma cut, and to stab andslash a target muscle. Michael Janich has more below.

Structural stops rest on the assumption that you have someplace to escape to and the threat will obligingly go down and stay down. If you’re attacked at home, or if you’re in a confined space like an elevator or stairwell, you have to fight until the threat stops. If the threat runs away or gives up after you cut his arm, great. But if your cuts are too shallow, if the threat simply picks up his weapon with his other arm or draws a backup, and is still able to harm you, the fight is still on.

Sayoc Kali teaches the concept of timers and switches. Timers are lethal attacks that will permanently end a target, but take time to bleed out. Switches are structural strikes that will permanently disable a target’s limb, but will not kill him. Learn to mix and match targets as the situation dictates. Against a single threat, flipping a switch or two may be enough to end the fight. Against a pack of enemies, you need to keep moving while defending against the possibility of hidden ranged weapons; you may have to employ a timer and a switch on every threat to stop them. A berserker or highly dedicated attacker may only stop when he runs out of blood and air.

With a knife, there is no clean distinction between lethal and less-lethal force. A quadriceps cut may non-lethally put down a target, but it can also sever the femoral artery and cause him to bleed to death. A cut throat is presumably lethal, but a shallow cut might not dissuade the threat. But to the courts, a knife is always a lethal weapon: even if you use a knife non-lethally you are only allowed to do so if your life is at risk.

Reading is no substitute for training and experience. If you dare to take up the blade, find a trainer and prepare for the worst. Study the human anatomy and psychology, understand the strengths and weaknesses of the blade, and be ready for a whirling maelstorm of steel and blood.

Further Reading

This is only a basic overview. There is much not covered here: psychology, anatomy, tactics, critical skills. For more information, please see below.

Other noteworthy instructors include Doug Mercaida, Terry Trahan, James A. Keating, Ed Calderon and Raymond Floro.