The horse does not want to depart on the left canter lead what can be done?

A horse that specifically resists the left lead canter departure while taking the right lead willingly is showing you a side-specific problem rather than a general canter issue. Side-specific lead resistance almost always has a physical, a strength and suppleness asymmetry, or a training history component at its root. Physical evaluation is the first obligation. A horse that will not take the left lead may be protecting his right hind leg, right stifle, or sacroiliac joint on the right side from the loading demands of the left lead departure. The left lead canter requires the right hind leg to initiate the footfall sequence by pushing off first and most powerfully — a horse with right hind soreness will avoid the left lead specifically because that departure loads the painful structure. Have your veterinarian perform a thorough lameness evaluation with specific attention to the right hind before proceeding with any training intervention. Assuming the horse is sound, the left lead resistance is almost certainly rooted in a physical asymmetry — less suppleness and strength through the right side of the horse's body than through the left. Begin the remedial work by addressing the right-side stiffness directly before asking for left lead departures. Spend significant portions of each training session working on exercises that develop right-side bend and right hind engagement — circles tracking right, leg yields moving to the right, shoulder-in on the right rein, and spiral circles that load the right hind leg. A small circle preceding the left lead departure is particularly effective for horses with specific left lead resistance. Ride a ten-meter circle tracking left establishing a clear correct left bend, then as you come off the circle maintain the bend and ask for the left lead departure. The circle has already done the preparation work — it has bent the horse, loaded the right hind, and positioned the body for the departure — and the ask simply needs to trigger the transition the preparation has made available. Patience with the timeline is essential. A horse whose left lead resistance is rooted in genuine right-side asymmetry developed over months or years will not correct that asymmetry in a week of focused work. Measurable consistent improvement over four to eight weeks of systematic suppling and strength work is a realistic expectation. Hold a longer timeline and resist the temptation to force repeated attempts at a departure the horse's body is not yet fully equipped to offer correctly.