Styles & Stances
Fighting Styles & Stances, by all means, are simply an abstraction. It seems to me that a few people here are wanting to see stances or fighting styles implemented, which is a concrete application of that which is abstract. Let me explain.
We already have a skills system set up. You learn sword skill as you train in it and use it. So what is sword skill? Your skill with using a sword, obviously, but it also entails combat training. You would learn to parry, riposte, how to move, how to stand, how to position your weapon, where you can throw strikes from, how to use your weapon to your advantage, how to deal with armored opponents, how to deal with shielded opponents, and even how to fight against other sorts of weapons.
How you stand when you're fighting is part of training. You can change your position and how you're standing, how you hold your weapon, which dictates what kind of attacks you might try. It's all apart of learning how to fight and how to fight against different opponents. Using one pattern of attack every time you attack will be quickly learned by your enemy, and you will be overcome. In fast-paced hectic combat, styles, stances, and even plans in general sometimes go awry and cease to matter while you're trying to survive. Hence you learn to fight, not any one specific style or stance. You learn to use your weapon as best you can, any way that you can, if you are to become skilled in that weapon.
Styles and Stances, in the DF system, really have no place at all. As you learn to use your weapon, and your skill improves, it reflects improvements on your technique with that weapon, as well as your style, stance, defense, offense, etc.
As far as martial arts go - that's a different kind of fighting. Normal western warfare -- Heavy Armored Combat and Eastern Martial Arts combat were terribly dissimilar.
A "sap" used to knock somebody unconscious, primarily for adventure mode might not be a terrible idea. You can attempt it through the "wrestle" menu maybe? IDK - just an idea. Or perhaps like I suggested with my version of the "Backstab theory" -- When stealthing/ambushing with a club, you gain a chance to knock a target out. If you're really lucky, you'll break their skull! Though you'd likely want a club or a slapjack of sorts to do such while "sneaking" in ambush mode, otherwise it probably wouldn't work out well. Normal weapons should just do normal bonus' (whatever they are) you get when ambushing. Bashing weapons should have a chance to knock out when ambushing?