Knives: How to make the cut is importantEvery officer thinks they know how to cut. I’ll bet you think so as well. I mean how hard can it be to cut someone? How to actually cut something or someone is very important: because if you’re not cutting with your knife’s edge then you’re not using it properly and you might as well be using a stick!

Most of you think that if you own a knife that you know how to use a knife.  However, it’s the same as having a firearm.  People think, “I own a firearm therefore I know how to shoot it.”  Is it a common trait that because we own something we think we understand its use because of that ownership?

Cutting is actually like punching in that it’s a learned skill, not a natural skill like hammering, slashing and hacking. I know I got some of you at both ends of the spectrum with that statement.  Some of you get a little excited with blood pumping and an adrenalin dump about slashing, hacking, and hammering.  Others went “yeecchh” about the same ideas. Let me say we aren’t going to do any slashing, hacking or hammering with our knives right now:  that’s NOT cutting!

Anybody can hack.  This is what you do with an axe or a cleaver. Hacking is commonly called chopping. You chop wood and you chop veggies. Slashing is the simple motion of a sword swinging from one extreme to another, from the open or closed position usually with a body caught in the middle. You’ve seen this in the movies as warriors slash at each other in mortal combat.

Hammering is that reverse grip or forward grip pounding or stabbing using percussive motion.   Think Anthony Perkins in Hitchcock’s Psycho does a great hammering / stabbing scene in the infamous shower scene: the knife going up and down as the chocolate sauce runs down the drain. Chocolate sauce looks like real blood more than anything else used in the movies especially in B&W movies.

Cutting? Cutting is putting the edge of the knife onto the target to use in a controlled simple motion. There’s a touchy-feely elegance to the act of cutting: the sensuality of drawing your edge through the target and the tactile response as it splits open the target’s flesh. The act of cutting is called slicing and you slice open the bad guy’s flesh.

Knives are edges that are designed to cut flesh. They weren’t invented or designed to do anything but cut flesh quickly and easily. They are matter separators, plain and simple. I assume most of you took basic physics in school.  I bet some of you remember elementary school where in both cases they taught us basic forms that had function: a wedge is one of those shapes. A wedge is really two inclined planes mounted back to back. Yes, a knife blade is a wedge shape in cross section. Wedges split things into two parts.

As matter is parted by the thin tip of the wedge and pushed up the inclined sides, a channel is made separating the two sides of the matter. We call this a simple channel or in a person a simple wound channel.  The longer the length of the edge, the longer and deeper that wound channel becomes as that edge is pulled or pushed along the surface of the cutting material. The longer the edge is in contact with whatever you want to cut, the deeper the edge will actually cut: not the harder, the faster or the stronger, but the longer!

By the way, that’s why knives have a slight belly to them.  They’re designed so that the arc that our arms make when in motion combined with the belly of the blade make an exact tangent “target to blade” to ensure a smooth deep cut throughout the arc of that motion. We’ll discuss blade shapes and geometry in a future article. It is fascinating how the shape aids in the cutting motion.

Let me bring this to a level anyone can understand. I’m sure you have all cut cucumbers, zucchinis, carrots and the like. I know they’re not bad guys but they make great stand-ins for practice. For clarity’s sake I’ll tell you that the tip of the knife is the toe and the butt of the edge is the heel. OK, let’s grab those veggies and begin our cuts. When you put your knife’s tip just past the zucchini and with a forward rocking motion bring the edge down and slicing it through the zucchini you are actually doing elegant cutting. This is one of those famous chef moves that leave everyone watching breathless as the chef effortlessly slides the knife in a continuous rocking motion, making the edge glide though whatever he’s cutting turning it into a pile of razor thin perfectly shaped slices. This is classic “toe to heel” cutting: which is where the old axiom of knife use came from, “if I can touch you, then you are cut already!”

Picture laying the edge of your knife on someone and with the same forward rocking motion as with the zucchini, all fluid with grace and no overt strength: slicing them open effortlessly and maintaining contact throughout the motion. What a stunning cut: perfect! In real time against a bad guy you don’t just lay the edge on to him but you intercept the bad guy which puts your edge into him and THEN you slice through him using the edge of the blade.

Of course the reverse is true, so if you put the heel of the knife’s edge on the zucchini and with an upward rocking motion bring the edge upwards and back towards you, you will be slicing through the zucchini with a draw cut. This is the classic heel to toe motion most of us think of as a knife cut. Again in real time you intercept the bad guy placing your edge into him and then you draw the edge through the bad guy slicing through him with the knife blade “heel to toe”!

Either of these two motions leaves you in a position to reverse the motion without losing contact and in the process doubling up your cuts: “toe to heel” leaves you all set for “heel to toe”. There’s no space or gap or vacuum for the bad guy to fill with a reaction or a counter that you can’t stick the edge immediately back onto him because as Professor Presas used to say to me “He cannot touch you..You are already there!”

So remember slashing, hammering, and hacking motions carry your knife through the target and past it or to the target and back away from it. Either way you are left with a gap or space, a vacuum that has no action or knife in it.  Usually that’s where the bad guy has a chance to do something. With the act of cutting, the slice keeps your knife right there in the field of action ready to cut forward “toe to heel” or backwards “heel to toe” as you need to without leaving a vacuum or space for the bad guy to fill. It’s a great feeling when you control the action and the bad guy with the edge of your knife!


Bram Frank has studied various fighting arts such as Wing Chun, JKD, and American Freestyle Karate for over 40 years. Currently, Bram is Director of Edged Weapons training at the S2 Law Enforcement-Security Institute. He is the SME (subject matter expert) on knives for the Hialeah Police Department. For the last 10 years, Bram has concentrated on the design and use of edged weapons / tools as an instrument of self defense and their use in military, police, and anti-terror applications. Bram was Black Belt Magazine’s Hall of Fame Weapons Instructor of the Year 2007. Action Martial Arts Magazine and their Martial Arts Hall of Fame in 2008 named Bram the Grandmaster of the Year 2008. He trains others in Europe, Israel, the Philippines, and the United States.