I've had numerous (written) conversations over the past few weeks with
assorted individual's who don't (seem to) understand what I mean, when
I say to “focus upon your own motions” (during the initiation of a
confrontation). The concept is not that hard to follow, yet I receive
numerous “questions”, in regards to that very statement, that are more
involved than what I'm attempting to convey! LOL.
Teaching students to rely on an "outside block" to prevent a punch from striking you in the face is (frankly) a wasted motion (if performed preemptively). Particularly if you misjudged which hand was going to be doing the striking.
Doing so will additionally allow the defender to (more easily) modify their defense as the aggression proceeds or if the circumstances change (as well as providing counter-attack possibility's).