What is counter-canter and how do you ride it?

Counter-canter is one of the most valuable and most systematically misunderstood exercises in all of riding — valuable because of the specific collection, balance, and self-carriage it develops in the horse, and misunderstood because many riders treat it as an advanced movement reserved for horses in formal dressage training when in reality it is an appropriate and genuinely productive exercise for any horse whose basic canter is established and whose training would benefit from the balance and collection demands that counter-canter specifically develops. Counter-canter is the canter performed on the lead that does not correspond to the direction of travel — the left lead while tracking right, or the right lead while tracking left. In normal canter the horse is on the inside lead corresponding to the direction he is bending and traveling, which is the mechanically natural and most physically comfortable arrangement. In counter-canter the horse maintains the established lead while traveling in the opposite direction, which requires him to bend slightly in the direction of the lead he is on rather than in the direction of travel — a requirement that demands genuine balance, genuine self-carriage, and the physical strength to maintain the canter correctly without swapping leads in response to the body's instinctive preference for the mechanically easier arrangement. The value of counter-canter comes directly from what it requires the horse to do to perform it correctly. The horse must carry himself in genuine collection because a horse on his forehand cannot maintain counter-canter without swapping leads, as the unbalanced forehand seeks the mechanical relief of the lead change the moment the direction of travel demands it. The horse must be laterally supple enough to maintain the correct slight bend in the direction of the lead throughout the curved track of the counter-canter. And the horse must be attentive enough to the rider's aids that he responds to the aid to maintain the lead rather than to the instinctive pull of the direction of travel. Introducing counter-canter begins with the simplest possible version — cantering a shallow loop off the long side of the arena that takes the horse only a meter or two off the rail before returning to the track. At this very shallow depth the demand is minimal but the exercise begins to introduce the concept of maintaining the lead through a slight change of direction without the lead change that instinct and imbalance would produce. As the horse manages the shallow loop with relaxation and without swapping, the depth of the loop is progressively increased over weeks and months until the horse can maintain counter-canter on a full circle — the demanding end of the counter-canter progression that requires the most collection, the most balance, and the most trust in the rider's aids. The specific aids for maintaining counter-canter are the same aids that produced the initial canter departure. Keep the outside rein of the counter-canter — the rein on the side of the leading leg — steady and consistent to maintain the bend in the direction of the lead. Keep the inside leg of the counter-canter — the leg on the side away from the leading leg — at the girth to maintain impulsion and prevent the horse from falling inward. The horse's nose should be tipped very slightly toward the leading leg rather than toward the direction of travel, which is the opposite of what normal canter bend requires and the specific detail that most clearly distinguishes a correctly ridden counter-canter from one where the horse is simply cantering on the wrong lead by accident.