This post is part of a series on martial development through the metaphor of Fiore's Four Animals.
"No creature can see better than I, the lynx. And this virtue puts everything in its right place and its measure."
Tom Leoni translation - Fior di Battaglia, Getty Museum
A technique could be mechanically correct in its execution but if it is not done at the right time or at the right distance it will be impossible to complete successfully.
Take parrying a blow with the longsword; How much distance do you need in order to be able to successfully respond in time and be in a mechanically sound place to defend against an opponent's attack? By subtly adjusting the starting position of my sword (from well back on the shoulder to lying just forward of the shoulder) I can dramatically reduce the time of my attack and make a student's successful action in the first situation into an unsuccessful one without making any other changes. By learning to spot these changes and manage them in your own fencing you will be far less easily deceived and gain a useful tool for succeeding in your practice.
Take any technique you are practicing and try it at different distances, both with your feet (stand closer and farther) and with your blade (change your starting position to put your sword closer and farther) and see how it changes the nature of the play and what you need to do to make it successful.