Please find below the source reference for the class:
This is about the four Leger (Guards):
Four guards alone,
keep these and forget the others.
Ochs Pflug Alber
and vom Tag should not be unknown to you.
Here he (Liechtenauer) mentions the four guards (Leger or Hut), which he considers useful. But first of all, one should not lie in these for too long, because Liechtenauer has a proverb: “Who lies there, is dead and who moves is still alive.” And this relates to the guards – a man should rather move with fencing attacks and techniques than waiting in the guards, which he may use to leave the Schanze (duelling yard)
The first guard is the Pflug (Plough) when someone puts the point in the ground in front of himself or to the sides. If you do this after the Absetzen (parrying) then it is called differently: namely Schrankhut or the gate.
The second guard Ochs (Ox) is the upper hanging from the shoulder
Alber (fool) breaks, what is being struck or thrust. And with hangings break swipes, the travelling after should follows instantly.
The third guard fool, is the low hanging with which you can break all strikes and thrusts if you know to do it correctly.
The fourth guard, from Tag (high guard) is also the long point. Who practices it with extended arms cannot be hit with strikes or thrusts. It may also hit the hanging over the head.
Also know, that all guards are broken with strikes, by courageously striking, so he must move up and defend. That is why Liechtenauer does not hold the guards in high regard but prefers to let his students try to gain the Vorschlag.
This is about the four displacements:
There are four displacements
that also open the guards.
Beware the displacements,
if they happen, you have to work hard.
If you have been displaced
and how it could happen
Listen to my advice,
swipe off and strike back quickly
Set the point onto four openings
and stay on it, learn this if you wish to end.
Who displaces well
can defend against many strikes
because with the displacements
you get quickly into the hangings.
Here learn that there are four displacements to both sides, one high and one low, and these break or open all guards. And how you lead away or defends against strikes thrusts or cuts from above or below this may be called displacing (versetzen). And if you have been displaced however this may have happened, so move off with the sword quickly and strike quickly again while you move in towards him.
Now if it happens that you displace or turn off a strike or thrust, so you should move in and follow at his sword so that he cannot move away. And then you can do as you wish – the more you hesitate the more you will receive damage.
Also you should wind well and aim for his chest with the point, so he has to worry.
Also a good fencer should well learn to bind at his sword and this can be done with the displacements, because these come from the four strikes, Oberhau (strike from above) and Unterhau (strike from below) from both sides and these move into the four hangings.
If one defends from above or below he should move in and get into the hangings, and should see to it that he turns away or leads off all strikes and thrusts with the front edge as it is done with all displacements.
Taken from the Nuremberg Hausbuch (MS 3227a), a German commonplace book thought to have been created some time between 1389 and 1494.