Could this refer to entering into Ringen range, or more broadly a caution about moving to strike from Zuefechten (the approach range)?
My current mood/line of practice tells me something like this. If you close in too early you are open to be attacked in either Vor or Nach, especially if you attack out of range--it leaves you as open as anything will in a fight.
Another option is that it's an exhortation not to go straight to grips every time. A couble of guys out here are very proficient wrestlers, and they always try to go for the Ringen instead of really working their blade. That may or may not work well in a fight, but it doesn't improve your knowledge of the sword. That seems to be a plausable bit of advice for someone studying the sword. Like our day now, we know that a gun is more effective, but we're trying to learn the sword...so we shouldn't Indiana Jones it at shoot our sparring partner, but rather we should fight to learn and to improve as a swordsman, not just as a fighter.
I like my first interperetation better, but I think that both have some possibilities.
Sen. Free Scholar
ARMA Deputy Director