I used think a forehand yield was a primarily western move, but it is something I now use a lot in my jumping and flat training! It allows me to isolate my horses front end and is also fantastic in jump offs when I want to do a tight turn or move their should across. It also preludes the shoulder-in movement.
To learn how to position your body to ask the forehand yield, check out my "Correct Position for Forehand" video, in my CORRECT POSITION FOR LATERAL MOVEMENTS video series.