There is such a thing as an interval into which not even a hair can be put. We can speak about this in terms of your own martial art.
“Interval” is when two things come one upon another, and not even a hairsbreadth can be slipped in between them.
When you clap your hands and, just at that instant, let out a yell, the interval between clapping your hands and letting out a yell will not allow the entrance of a hairsbreadth.
This is not a matter of clapping your hands, thinking about yelling, and then doing so, which would result in there being an interval in between. You clap your hands and, just at that instant, let out a sound.
In just the same way, if the mind stops with the sword with which a man is going to strike you, there will be an interval, and your own action will be lost. But if in the interval between your opponent’s striking sword and your own action you cannot introduce even the breadth of a hair, your opponent’s sword should become your own.
In Zen discussions we have the same thing. In Buddhism we abhor this stopping and the mind remaining with one thing or another. We call this stopping affliction.
It is like a ball riding a swift-moving current: we respect the mind that flows on like this and does not stop for an instant in any place.