If someone is resting in a guard, making an earnest attack against the head or body is usually a really bad idea. Even more so if it is a particularly strong guard like Pflug. In order to unsettle the opponent and constrain their actions, you can use what dall’Agocchie calls a “provocation”. In MS I.33 this is known as an Obsessio, which is translated as “siege” or “displacement”. This particular provocation is one of Lichtenauer’s four principle displacements, the Vier Versetzen.
When your opponent is in right Pflug, step with your left foot and throw a Schielhauw (squinting strike) to roughly the middle of his sword. This will be a right Schielhauw, so your wrists will be crossed* and both points will be to your right. Then immediately step forward and thrust while winding your pommel under your right arm.
Be careful that you don’t over-wind. As you thrust you want to put the long edge on his sword and keep it there. If you wind too far you’ll put your outside flat against his blade and lose control of his sword.
I need to stress the immediacy of the thrust. As soon as you complete the Schielhauw you need to either abort or commit. If you dally, he’ll be able to wind into a better position and you’ll be the one being sieged.
So far we’ve been talking about breaking right Pflug. Left Pflug works the same way, only you’ll have the right foot forward and use a left (uncrossed) Schielhauw as your opening action.
For every technique there is of course a counter. Mair presents his, and the counter-counter, in The Schillerhaw from Both Sides. I hope to cover that tomorrow.
* Meyer says that the right Schielhauw is thus also a Krumphau because the wrists are crossed.