Several problems are created when a horse cuts the corners of
the ring on course. First, the horse's weight is distributed too
heavily toward the inside of the turn, so that the animal is
unbalanced on its approach to the upcoming line. Second, this
habit is usually accompanied by the horse being bent in the wrong
direction, so that its vision is jeopardized. Third, by cutting
corners, the horse leaves the rider with fewer strides in which
to make adjustments following and leading into the lines of
fences.
The main thing to remember in solving this problem is to push the
horse to the rail with an inside leg and an inside indirect rein,
rather than pulling it to the rail with an outside hand. In
practice sessions, wherever the horse starts to cut the turn, do
a downward transition to the walk and push the horse toward the
rail using the aids given above. In competition, if the horse
tries to cut the turn, shift your upper-body weight slightly
toward the outside of the turn while using the aids given above.
This will help adjust the vertical plane of the horse's body back
to center, making it more difficult for the horse to cut in.