There are two ways the Zwerch (Thwart cut) can defeat Tag (High guard). The difference is not so much in the action itself, but rather the timing and distance.
When Given a Tempo
There are several ways an opponent can give you a tempo, a time to act. These are summarized as,
- After you have parried your opponent’s attack
- After your opponent’s sword has traveled past your body
- When your opponent lifts his hand in order to strike
- When your opponent injudiciously changes his guard
- When your opponent steps forward (with his front foot)
In our first scenario, numbers 3 and 4 both refer to the opponent lifting their sword into Tag. As they do so, you may strike with either Zwerch while taking an off-line step. Begin this action as soon as you see them start to move so that your strike lands as they complete the transition into Tag. So not allow them time to begin their next action.
Scenario 5 usually occurs when the opponent steps into wide measure. As a reminder, “wide measure” is the distance from which they can land a strike using a step. If they could land a blow without a step, they would be in “narrow measure”.
If someone steps into wide measure without cutting or otherwise presenting an immediate threat, step at the same time as them and counter their inaction with a Zwerch.
Likewise, if they are in measure and shuffle their feet or otherwise perform a non-productive action, attack before they settle into their new posture.
As a Provocation or Siege
If the opponent is already settled into their posture, their Leger (Camp), then the situation becomes more-tricky. A direct attack should not work. If it could, then they are not in a true guard and you are just punishing them for doing something wrong.
But let’s assume that they properly formed their guard. They know what attacks you are likely to make and have practiced the counters for each. So we need to provoke them into leaving the safety of their guard. This is where the word Versetzen (Displacement) comes into play.
To displace them from Tag, we use the Zwerch. The arm motions are the same, but the step is made shorter and possibly more to the side. The goal is to give the illusion of a deep cut, when actually you are just lining up the point with their face.
This will put you in a posture that resembles the below composite image, though the footwork will not necessarily match.
This is known as a “counter-posture” or “siege”. Once you are in this position, your opponent may hesitate. If that happens, thrust. Your point is already on-line and the completion of your attack will support your parry if they later decide to cut from above.
If your opponent does not hesitate, then the most likely response is to parry your sword with a high cut. Since you are effectively in an extended Ochs, this cut should not threaten you. Though it should be noted that your hands may be jeopardy if you stepped too narrowly, so ensure that initial Zwerch was made with an off-line step.
The opponent is now in the Nach (after). Another way of saying this is that they opponent is in “obedience”, meaning they are forced to respond to your actions rather than attempting their own devices.
As their blade makes contact with your sword, you can begin the customary second Zwerch to the other side. If you are certain the opponent is attacking your sword, rather than your head, you may even begin your second cut before the blades make contact. This is a type of feint known as a Fehien (Failing) because the blades fail to connect.
Alternately you may remain in the first counter-posture and thrust from the bind. Or use any other technique that you see fit. The point is the opponent has left their safe space and is now a tempo behind as they try to respond to your actions.
Grauenwolf's Study of Western Martial Arts 