From Ringeck:  Note the mutating [Mutieren] Deploy the mutating thusly: When you bind him with the over-hew (or otherwise on the sword), then wind the short edge upon his sword and drive well up with the arms, and wind your sword's blade outside above his sword and thrust him to the low openings, and this conducts to both sides. From Pseudo-Peter von Danzig: Here mark how one shall drive the Mutating to both sides: Mark, when you hew strongly on him from above your right shoulder to his head, if he parries and is Soft on the sword, then Wind on your left side with your short edge on his sword, and drive up well with your arms, and drive in with your sword’s blade above over his sword, and stab into the lower opening. Another: Mark, when you hew to his head from above your left side, if he parries and is Soft on the sword, then drive up with your arms and hang in the point above over his sword, and stab into the lower opening. Thus you may drive the two techniques from all hews thereafter, as you find the Weak and Strong on the sword. From Ringeck:
The text and the gloss about the doubling [Duplieren] and about the mutating [Mutieren]: how they break the four openings.
If you wish to reckon yourself,
Artfully break the four openings:
Mutate right below.
I say to you truthfully:
No master defends themselves without danger.
If you have understood this properly,
He may hardly come to blows.
Gloss. This is when you wish to reckon yourself upon another such that you wish to break the four openings with art: so conduct the doubling [Duplieren] to the upper openings against the strong of his sword, and the mutating [Mutieren] to the other opening. Thus I say to you truthfully that he cannot defend himself from that, and may neither come to strikes nor to thrusts.
The doubling [Duplieren]
Item. Note, when you cleave-in with the wrath-hew (or otherwise high), if he displaces you with strength, then in-the-moment shove your sword's pommel under your right arm with the left hand, and strike him through the maw, with crossed hands, upon the sword behind his sword's blade (between the sword and the man); or strike him with the play upon the head.
From Pseudo-Peter von Danzig:
Here mark how you shall drive the Doubling [Duplieren] to both side