Yeah...I had a friend who was a pistol instructor (passed away some years ago) who started his lessons with a blank piece of paper as a target. I believe that the exercise was to train the shooter to focus on the front sight as opposed to something like a bull that was downrange.
It works. It is a good exercise for anyone shooting irons.
"Only hunting and mountain climbing are sports. The rest are just games." - R.Ruark
NRA Life Member