Langenschwert
Master Black Belt
Fighting against weapons are the same as fighting against an unarmed person, except if you screw up the consequences are worse.
Your enemy's body has to move the same way, he'll come at you from the same angle he would without a weapon, so do any technique, just don't get stabbed.
just move, hit, and turn. He'll fall down. You might be a bloody mess, but he'll fall down.
OK, asides from universals such as range and timing, you couldn't be more wrong.
Weapons change everything. All the chokes and submissions in the world won't help you against a knife fighter... he'll stab you while you're busy applying the choke, in say the femoral artery if you're trying to choke from the rear. Punches may not do anything... you can take a punch to give a punch, so you can take a punch to give a fatal stabbing, can't you? If you take him down, he'll stab you on the way to the ground. There's a reason why medieval manuals only talked about knife fighting on the ground when the combatants were armoured. If you take a knife fighter to the ground and go with him, the arm must be broken. If you take him down and remain standing, that's a bit better, since you're in a nice position to RUN LIKE HELL.
Bypassing even the best knife defences is a simple matter for a decent knife fighter. A knife turns even a weak jab into a killing stroke, and a glancing blow into a life-altering injury. I'm not saying that knife defences are impossible, I'm just saying that it's a different beast, one that has to be trained religiously and fantatically to have a reasonable chance of success. Also, knife defences are unlikely to work against a duellist, someone who makes an art out of knife fighting. Look for "Piper System" to get an idea of what facing a knife-fighter is really all about.
Don't even get me talking about trying to defend against a sword.
Best regards,
-Mark