How do you introduce counter-canter to a horse for the first time?

The introduction of counter-canter should be as undramatic and gradual as possible — the goal is for the horse to discover that it can hold a lead through a slight curve without it being a significant event, not to challenge the horse immediately with demanding counter-canter exercises. Clinton Anderson's approach is to begin on a very shallow loop. After loping a large circle on the correct lead, instead of continuing the circle, he straightens the horse briefly, then curves it very slightly in the counter direction — just a hint of curve, perhaps ten or fifteen degrees off straight — and immediately rewards the horse for maintaining its lead through that slight change. The first counter-canter experience should feel nearly like going straight. From the shallow loop, the curve is gradually increased over multiple sessions. As the horse confirms its ability to hold the lead through a shallow curve, the curve becomes a genuine corner, then a half circle, then a full circle — always only progressing when the previous curve is managed calmly and correctly. The specific aids for maintaining counter-canter are critical from the first introduction. The outside leg — which in counter-canter is on the same side as the lead — moves slightly behind the cinch to prevent the hindquarters from swinging to the inside and to maintain the horse on the correct lead. The inside rein provides a very slight opening toward the direction of travel without bending the horse's neck away from the lead. These aids should be consistent from the first session so the horse develops a clear association between the specific aid position and the counter-canter exercise. Pat Parelli introduces counter-canter through his figure eight exercise, allowing the horse to naturally find the counter-canter as it lopes through one circle and begins the other without being allowed to change leads at the crossing — a natural and low-pressure introduction to the concept.