It's time for more post-VISS rambling! Rather than talk about concrete technique type things, I'm in the mood to kick around some higher conceptual type things - specifically tempo, measure, the relationship between them, and what it means for the fighter.
I tend to work from the Italian framework of rapier theory. In general, this means that closer is better. If my opponent gives me a tempo to work with, I'm generally going to respond by closing. (Striking with my sword is closing of a sort, too. It's just a very final closing.) If I can't close safely, I want to set myself up to be able to do so. If I can ever avoid backing up, I will. (Ever notice how many actions in the Italian - and many other - manuals involve closing, and basically none involve giving ground? I heard some good theories about this from Tom Leoni - in short, if you're on a battlefield you don't want to back up because the ground is littered with tripping hazards and falling is death. In a duel, leaving the circle is losing. Not stepping into areas that you don't have eyes on can dramatically limit these issues.)
The problem with being close to my opponent - ideally close enough to strike with an extension or at most a "firm footed lunge" - is that any tempo I work inside gets shorter and shorter the closer I get. In terms of keeping myself alive, I don't like working inside a short tempo. I want more time to think, to react, and to respond to the attack. If I'm the one doing the attacking then a short tempo is awesome, but the first thing we need to be concerned about is defense, and only then do we consider offense, so there we go.
This leads to something which I've started to mentally refer to as the economy of tempo and measure. They seem to work on an inverse relationship; if you want more of one, you're giving up something from the other. There are some ways you can impact the exchange rate for specific actions, but you're still working against that relationship no matter what. We've all played with this, whether we really understood what was happening or not. Any time you lean or step back as you parry, you're selling off distance to increase the length of the tempo you're responding in. If you close with your attack, you're selling down that tempo to buy back some of that distance.
The more I mull this idea over, the more it gets increasingly clear just how much these two concepts encompass so much of the fight. This was pretty obvious to me before, but now it's become obvious in the way that the sun is kind of a thing that you notice in the sky.
Partly because of an increased mental emphasis on doing drills correctly, I'm looking at setting up exchanges to be what I want them to be. That's far from universally successful for me, but the point is that one of the keys to this is understanding how what you're doing will be impacted by the tempo and measure you're working within, and how it will impact them in turn. If I'm closing, I want to set things up so that whatever my opponent does will require a far longer tempo than what I plan on doing. Sure, realistically, there'll be people who just have insanely fast hand speed, and that's fine - but if you're able to play with the fundamentals really well, that doesn't matter because they just need to take such a huge tempo to strike you that even if they're speeding through the motion, you still have time to strike them safely.
This really feels to me like one of those Matrix moments. Once you've started to see the source code, you can't unsee it. This doesn't remotely mean that body mechanics, moving in good order, or any other fundamentals are unimportant, or even less important. Rather, it highlights the importance of training all of those things so that you can perform them so efficiently that you can shave down the tempo you need, or have a much more fine control over measure.