I'm starting this series off with a weapon that doesn't get a lot of love (outside of Magic User circles) - the dagger. I'll be continuing on with the short, unbalanced weapons (axes and maces), then the swords (arming and long), and eventually the polearms (spear and poleaxe). I may do more later on, but most other weapons are pretty similar to one of these - enough that they can probably be treated the same mechanically.
The medieval dagger of the period was about the size of a really big carving knife - the blade would be about 12"-18" long, with an extremely stiff blade. It's primary purpose was piercing, but it would typically have at least one sharp or semi-sharp edge.
|Rondel Dagger c. 1350 found in the Thames River, London - image from Wikimedia Commons, courtesy of Dana Williams|
Daggers typically deal low damage in RPGs, to distinguish them from the bigger weapons. I would posit that the 0e system of d6 across the board is not that far off. All Medieval weapons were more than capable of killing a normal, unarmoured man outright in a single blow, and this is how Oe works.
The 12" blade of a dagger can do some really serious damage to the human body. A blow to the head will pierce the brain, likely instantly killing the victim. Neck shots will sever arteries, cut the windpipe, or damage the spinal cord. Blows to the trunk are typically less useful, as the ribcage is pretty tough, but a blow that comes down through the collarbone or between two ribs could easily puncture a lung. Stabs to the abdomen can pierce the liver, kidneys, or other vital organs, leading to rapid death from internal bleeding.
That said, many of the blows from a dagger would be to the hands and arms, where they would be painful and dangerous in the long run (i.e. slow bleeding and infections), they likely wouldn't put you out of the fight. Glancing blows will slice the victim up, but again, likely not enough to put the person out of the fight.
This is my justification for giving the dagger 2d6-TL (2d6 Take Lowest) - enough that it can be very dangerous, but blows from it typically will not kill you.
Usage Vs. Armour
The Medieval dagger was also a valid tool against an armoured opponent. Its stiff blade and sharp point made it ideal for forcing through chain mail, and it can still be used in a grapple once other weapons have been abandoned.
In a close fight between armoured opponents with daggers, each will be seeking a weak point to drive it in, and there are a few choice targets. Depending on the helmet, there may be some great targets on the head.
If the helm is unvisored, like the popular kettlehelm or early bascinets, the face has only thin bone between blade and brain, and is an excellent target.
If the helm is visored, like the popular hounskull bascinet, it may be possible to open the visor and attack the face.
Lastly, if the helm is one solid piece, like a greathelm, the eyeslits can be a target. This is probably most practical if the victim is pinned on the ground, limiting their head mobility, as the eyeslit is a very small target, and they often had flanges to direct thrusts away from them.
After head strikes, the neck is another good target. In-period, the neck was often defended by a plate gorget (which would be more or less impermeable), with or without an aventail of mail around it. In a very close grapple, the attacker might be able to lift the back of the aventail, and get his dagger in the back of the neck, severing the spine or major arteries, or plunging the blade down in the hopes of hitting the heart or lung.
Barring any of those options, the armpits were typically only armoured with chain, which a dagger could be forced through.
|Plays of sword and dagger, from the Getty MS Ludwig XV 13, by the Master Fiore Dei Liberi c. 1410.|
While the dagger is rather small, it is not useless for defending yourself - anything that you can directly control an enemy weapon with is better than nothing! In fact, you can make most of the dagger defenses with any kind of similarly-shaped object - a stick, for example.
I've rated the dagger's defensiveness as low, because it is so small it's easy to screw up your defense, and it can be overborne by powerful weapons like the poleaxe.
A defender with a dagger facing someone with a superior weapon would be trying to do a few things, typically.
Controlling the opponent's weapon is always the first priority, as killing them is little good to you if they kill you at the same time. The dagger doesn't offer the leverage of a sword, or the reach to strike from the bind (i.e. weapons crossed). Therefore the person with the dagger will likely try to transfer control of the opponent's weapon from the dagger to their offhand after parrying an attack.
From there, they can seek a lock (like a key or armbar), a disarm (most viable against a one-handed weapon), probably all combined with an attempt to maneuver in beside or behind the opponent for an opportunity for one of the lethal strikes I described above.