The first technique for facing another fencer in Alta is easy enough, just a couple of diagonal, descending cuts followed by a rising cut.
Accordingly, posing the case that you and your enemy are in guardia alta, and that you are the attacker, you can throw a mandritto at his sword hand which will go over your arm, and then turn a riverso also to that hand. Then ascend with a montante to return to guardia alta; if you will do these three blows, your enemy will be unable to throw anything toward you that could offend you, because he would always come to collide his hand into your sword.
But the sentence seems rather problematic,
But if it does not please you to throw the three aforesaid blows, you can turn a riverso to his thigh.
Throwing a normal riverso to the head or shoulder from Alta is easy enough, but if you go all they way down to the thigh the buckler gets in the way. So you have to do this kind of weird S-curve that is slow and leaves you exposed.
We thought that it might be a mistranslation but the transcript clearly says ‘riverso’. Also, the buckler can easily protect the thigh from a mandritto.
So that’s where we’ve been stuck for the last few weeks, then something clicked.
Turning a Fendente Mandritto into a Rivserso
The first mandritto doesn’t actually say what angle you should cut at. You could use a diagonal cut, but the with the right footwork you can position yourself to throw a nearly vertical cut to the wrist that is tighter and faster.
Or instead of hitting the wrist, you can continue straight down in the slot between your buckler and his. Once you clear his buckler, angle the cut into the right side of the nearest thigh.
Original illustration by Giovanni Rapisardi
With a heavier sword such as a messer you could conceivably cut off the sword hand and deeply wound the thigh in a single blow. With an arming or side sword I think you are more likely to merely cut to the wrist bone, probably breaking it.