The short answer is you don’t use a sword to disarm someone with a knife because you don’t need to. The match up of sword versus knife is the original, “don’t bring a knife to a gun fight.” Outside of use as an offhand parrying tool, we don’t bring knives to sword fights either.
The reason why is range. The average longsword is thirty-six to forty-eight inches. If that’s the type of sword you envision your character fighting with then that’s the distance the dagger wielder would need to travel just to break past their guard, during which time the dagger wielder would not be in a position where they could reasonably hit anything. Daggers are short-range melee weapons used to enhance hand to hand combat. The sword is a mid-range weapon. So long as the character with the sword keeps their opponent at blade point and possesses reasonable skill in keeping their guard up, the one with the dagger can’t do anything. The sword character is in more danger of the character with the dagger impaling themselves on the blade in an attempt to reach them.
Despite what most fantasy literature or video games tell us, knives necessitate a very aggressive fighting style. The goal isn’t pinpoint targeting of vital organs because it isn’t necessary. The goal of knife combat is to land as many lacerations or stab your opponent many times as possible within a short time frame while, reasonably, maintaining your own safety. Why? Because it works. In the real world, it doesn’t matter so much where they’re hit so long as they’re bleeding. The more blood the better. At the end of the day, twenty stabs to the stomach is just as good as tearing through the carotid artery. Less fancy, maybe, but the stomach is a simple, easy target that can be struck with a basic bullrush. This is what makes knives such effective weapons in their home range. They’re simple to use, easy to learn, and, because the expectation is fighting unarmored opponents, every landed strike, stab, and laceration builds into deadly. Once fighters see their openings and move into range, combat is lightning fast, and the fight is over very quickly. Strikes should flow like hand to hand, moving in combinations from one to the next.
Now, let’s talk about disarms.
There’s a lot of misunderstanding of disarms by those who don’t practice martial arts. Disarms get treated like a magical panacea to end a fight. And I get it, they’re really cool to watch.
The answer is pretty simple. Physics. They’re an extension of grappling and joint locks with the same principles applied. The body’s muscle system works on a system of pulleys. When the pulleys are disrupted, the body stops working. The goal of a disarm is to get the enemy’s wrist, fingers, arm, legs, whatever rotated on an unnatural angle and apply the right amount of leverage that forces them to let go of their weapon. Or, breaks their joint. Simple in concept, difficult in practice. And, in point of fact, it’s extremely difficult in practice.
Knife disarms in self-defense are taught under the expectation that your opponent is armed and you are not. They are extremely risky. They’re done in the hand to hand range. The catch points are in the moments before or after your opponent’s arm reaches full extension. Fail to get out of the way in time and get slashed or stabbed. Fail to move at the right moment before the elbow fully extends and get slashed or stabbed. For reference, there are variants practiced in the military that involve sacrificing body parts to the effort. When the hand with the knife is captured, the way to take it is by rotating the knife’s grip against their thumb rather than against the other four fingers. As pain is applied with the unnatural angle, the body’s sense of self-preservation kicks in to prevent dislocation and they let go.
Swords cannot conventionally disarm knives the way we’d disarm an opponent with a sword, outside of attacking the hand that holds the weapon. The knife/dagger is too short for the blades to get into a rotational lock, so it can’t be popped out of the hand in the same fencing trick we see on the Mask of Zorro, Highlander, or other swashbuckling films/shows. Besides, someone with a knife isn’t going to be fencing a swordsman.
The goal of the disarm is the negation of your opponent’s ability to fight. For those who don’t practice, it’s a nice dream. The belief that the fight ends when the weapon is removed. Unfortunately, life isn’t usually that clean.
In the years Starke and I have spent running this blog, I’ve noticed that one of the most difficult concepts for writers lacking in experience with weapon handling to grasp is range and its importance in combat when it comes to mixed weapons. Video games are a partial contributor here, I think, along with television. Neither handle the disparate difficulty created weapon length with any particular accuracy. And, honestly? It can be difficult to wrap your brain around the concept without visual representation or learning to gauge distance to hit.
Your swordsman is in a position to completely control the fight and negate their opponent without taking their weapon away. So long as they maintain their distance and keep their weapon in its effective range, they can wait them out if that’s their preference. They don’t need to be the more skilled fighter. The range difference provided by their sword makes up for it. That’s the difference between four to ten inches of steel and thirty-six.
Your character with the dagger isn’t completely down and out, but, regardless of their skill level, this is a situation where they are an extreme underdog. At least, if they have no special powers or abilities granted by your setting to give them an edge. They’ve also chosen not to fight on a field which benefits their weapon and fighting style.
It’s important not to internalize the idea that the sword is the better or superior weapon. It’s not. The sword has the same issue as the dagger against polearms. The sword can be undone by a wooden staff. Every weapon has situations where they shine and situations where they don’t. Weapons are situational in their use. Each one serves its own purpose on the battlefield, regardless of whether that use is more general or more specialized. They require their wielders to engineer situations or choose battlefields where they have an advantage. That’s why hyperspecialization is bad. Anime has its characters hyper specialize in order to force visual variety and, often, especially in shounen, to force its characters to fight creatively. This is a huge factor in their character arcs and evolution. It’s a useful technique to learn, just remember that visual mediums don’t translate to written with the same effect.
