Modern Self-Defense Tactics with a dagger

When it comes to fighting knives, the dagger enjoys an elite status that few other blade styles can match. Historically, daggers have always been revered as incredibly potent weapons, whether they really deserved that reputation or not. For modern self-defense, however, historical reputation isn’t good enough.

For self-defense, we need real performance. To that end, let’s take a look at what really constitutes a good dagger and how to take advantage of those attributes with proper skills and tactics.

For the purposes of this article, I’m defining a dagger as a true double-edged knife capable of serious cutting performance with either edge. Based on that definition, single-edged knives with false edges—sharpened partial edges on the spine of the blade—also technically qualify.

Single-edged knives with swedges (unsharpened back bevels), spikes, or any other designs that fall short of truly functional edges “don’t make the cut”—both literally and figuratively.


Double-edged knives are illegal to carry in many jurisdictions, so structuring your edged-weaponbased self-defense tactics around one may box you into a legal corner.

As always, it’s your responsibility to do the homework on the laws where you live and areas where you travel.

In addition to the term “dagger,” also beware of “dirk” and any verbiage that specifically addresses the number of sharpened edges permissible by law.

Against an overhead attack with a hammer

Against an overhead attack with a hammer

Some laws also prohibit the carry of knives that are purpose-designed as weapons. Daggers make poor utility tools and are typically recognized more as weapons than general-purpose knives. When in doubt, err on the side of caution and carry something single edged.

Design Considerations

With very rare exceptions, folding knives do not lend themselves well to double edges. The reason is that the spine of the blade usually stands proud of the handle when the knife is closed.

If it were sharpened, you’d have a sharp edge exposed—even when the knife is closed—so carrying and deploying it would be dangerous.

The only way to safely carry a double-edged folder is to have a design that allows the blade to fold completely within the handle. Balisongs do this best. The early custom versions of the Applegate-Fairbairn Folder were also double edged, but most folder designs don’t allow it.

With very rare exceptions, folding knives do not lend themselves well to double edges.

The dagger-armed defender first executes a two-step Hubud parry from the Filipino martial arts to deflect the strike

The dagger-armed defender first executes a two-step Hubud parry from the Filipino martial arts to deflect the strike

The other issue with double-edged folders is that cutting with the back edge of the blade places a lot of stress on the lock mechanism. If it’s not up to the task and the folder “lives up to its name” at the wrong time, you could suffer serious injury.

If a folder isn’t an option, obviously the remaining choice is a fixed blade. While fixed blades are simpler, stronger, and quicker to get into action than folding knives, from both a comfort and legal perspective, they can also be challenging.


Knife’s Edge Geometry

Regardless of which option you choose, pay close attention to the knife’s edge geometry. In order to cut effectively, its cutting edges must be reasonably thin and acute.

This is a challenge with daggers because their double edges mean that the primary bevels for each edge must be shorter than if the same blade were single edged. The shorter the bevel, the more obtuse the edge angle and the poorer its cutting ability.

Many iconic daggers—like the famed FairbairnSykes commando knife—suffered from this shortcoming.

With very rare exceptions, folding knives do not lend themselves well to double edges. The dagger-armed defender The dagger-armed defender


A high-performance dagger blade is almost like laying two single-edged knives spine to spine. Both cutting edges should have long bevels and acute terminal-edge geometry. Broad blades, thinner blade stock, and hollow-ground bevels all help achieve this.


The primary advantage of a double-edged blade is that it cuts in both directions. This quality allows it to be used with both conventional “edge-out” skills and “reverse-edge” tactics without having to adjust your grip.

That means you can integrate the skills of these two different approaches to knife tactics to create a “hybrid” system that allows you to take advantage of targets that face toward you and those facing away from you with equal ease.


For example, if an attacker swings a weapon at you with a high, forehand motion. Then, the inside of his arm—and all the high-value targets it offers—is exposed. Outward cutting strokes with either standard or reverse grip could target the flexor tendons, muscles, and arteries of the inner forearm. This could also target the bicep muscle and the key nerves and the brachial artery just below it.

Once you’ve followed through on your cut and your knife is past his arm, aim for the triceps muscle, drawing the near edge of the blade back toward you through the target.

This powerful pulling movement takes advantage of the strength of your back muscles. It also severs the muscle that your attacker needs to extend his arm and swing at you again. Two cutting edges can be better than one, but only if you wield them with smart tactics.

Martial Blade Concepts