Piaffe is a high school dressage movement where the horse is highly collected and the legs move up and down in diagonal pairs (like a trot) while the horse should not move forward.
The centre of gravity of the horse during piaffe should be more towards the hind end, with the front of the horse highly mobile and light in the hand.
It was originally used in battle to keep the horse focussed, warm, and moving, ready to move forward into battle.
In modern times the piaffe is mostly taught as an upper level movement in Classical dressage and as a Grand Prix level movement.
