How do you fix a horse that anticipates the canter transition in dressage?

A horse that anticipates the canter transition — tensing, breaking, or beginning to canter before the rider has applied the canter aid — is showing a pattern that develops when canter transitions have been practiced at predictable locations in the arena or when the horse has learned to read the rider's preparatory tension as the actual canter cue. Anticipation makes the horse difficult to ride smoothly in any movement near the locations where canter is typically requested and creates the building tension in the trot that often produces irregular or poor-quality transitions even when the horse does wait for the cue. The correction requires systematic unpredictability: varying the locations where canter is asked so the horse cannot predict based on position where the transition will occur, and practicing trot work through the areas where canter is typically requested without cantering. Riding actively forward in trot through the areas where the horse typically anticipates — maintaining the trot and focusing on forward energy and rhythm rather than preparing for canter — directly contradicts the anticipation pattern and teaches the horse that being in that location does not automatically predict a canter. Practicing counter-canter through the same locations where the horse anticipates a transition to the true lead resets the horse's expectation, because performing canter work in the unexpected direction at those locations teaches the horse that the rider's aids rather than the location determine when and which gait change is requested. Interspersing many canter transitions with occasional trot-only passes through the same locations — sometimes cantering, sometimes continuing in trot — ensures the horse is waiting for the actual aid rather than location-based anticipation. Addressing the rider's own preparation — ensuring that the half-halts and position changes that precede the canter aid are not so dramatic that the horse reads them as the canter cue before the actual leg aid is applied — removes one of the most common sources of anticipation.