"you must not remain in one guard, but always move from one to another and transform one into another, it will behoove you to pay good attention to how these guards follow from one another" - Joachim Meyer
"now as regards the postures, I would not have you remain long in any of them, since they are not invented or devised for this purpose...linger in that furthermost point for just a bit, almost only for the blink of an eye" - Joachim Meyer
Meyer is clear that the "guard" postures are not points that you hold but points that you transition through while making your cut or thrust. They represent moments in time where if your opponent reacts and your intended action doesn't look so good, you can change your intent. They also communicate your intent to your opponent who will have to react, in fairly set ways, to your projected intent. This conversation is the Art.
The human brain is hard wired to spot something that isn't moving suddenly bursting into movement, it's the ambush predator response that triggers our startle reflex. However it is remarkably less adroit at spotting one movement turning into another movement. So if you want to give your opponent the minimum possible time to react or understand your actions then from the moment your opponent sets eyes on you, you've got to keep moving.
Ox, Plow, Day and Fool are the basic guards or postures. Ox and Plow are the positions you make when you parry and between them they can cover all the four openings. They also threaten the thrust and provided the point is on line must be dealt with by your your opponent before they can safely attack your body.
Day and Fool are not intended as parries but they leave the sword out of reach of engagement and do not have to be on line like a thrust does, therefore they more convincingly threaten an opponent who again will have to deal with this threat before attacking your body.
People often comment on how Meyer has "lots of new guards." I would disagree about the newness, he is just being more explicit then previous treatises on how you actually cut. I'll illustrate this below, bearing in mind these woodcuts below were intended to illustrate Meyer's devises not the guards in sequence so you have to use a little imagination.
The straight cut from above
The straight cut from below
"if you go up from below with crossed hands to parry, you again find three postures, namely at the beginning the Irongate, in the middle the hanging point, in the end the Unicorn up at the top" - Meyer
I've used Meyer's crossed guard because he doesn't show the Irongate in the Longsword, but I might have been better repeating the Fool.
Diagonal cut from above
"you come first into the Wrath Guard, from which the cut takes its name...halfway through the cut into Longpoint; and at the end into change" - Meyer
This sequence of drawing, I think, illustrates Meyer's stances quite well. Beginning stance in Wrath, middle stance in Longpoint and finally end stance in change.
The basic rule is: as you cut you should be passing through three of Meyer's guards, which is handy to know.
Really important point: note how in the final set of plates the feet are turning with the direction of the weight. As the weight goes forward the lead foot turns parallel and the rear foot perpendicular. As the weight goes backward the rear foot goes parallel while the front foot is perpendicular. This is because they are swivelling their hips to get the whole body into the cut. Don't ignore this, it's a powerful part of the technique for a full "wrath" cut.
It's possible to do this by rotating your feet on your heels, but this is very unbalanced and doesn't use the extra spring from using your whole foot. Do this instead by swivelling on the balls of your feet.
- Grab a beach ball or a gym ball and hold it with your arms fully extended. Start in beginning stance and move in a circle as if around a clock face while moving through the beginning, middle and end stances. There are no prescribed stances to arm positions, but you want to be in end stance when sweeping the ball forward and in middle or beginning stance when sweeping back. Keep your feet on the balls or mid foot, hips moving in a horizontal line and upper body making an slight arc.