rider may ask for a canter depart (aids for the horse to step into the canter) on the flat from trot, walk, or halt. There are three ways to ask for the canter depart while on the flat, which may be used according to the horse's level of training. Additionally, the rider may ask for the canter as the horse jumps a fence (if the fence was taken at the walk, trot, or halt) or may ask for the horse to switch leads over the fence. Outside lateral aids Aids: The rider applies the outside leg slightly further back from its normal position, which activates the outside hind (the first beat of the intended lead). At the same time, he or she uses the outside rein to flex the horse's head toward the outside, which frees up the animal's inside shoulder, encouraging it to fall into that lead. If the rider were to ask for the left lead, for example, he or she would apply the right leg behind the girth and use the right rein to turn the horse's head to the right. To make the rider's intent even clearer, the horse may be angled slightly toward the outside rail of the arena, which will guide it into taking the correct lead as it goes towards the unobstructed inside, and also discourages the horse from simply running onto the forehand. Purpose and Drawbacks: These aids are preferred for green horses, as they are clear and simple. However, they bend the horse in the direction opposite of the turn, resulting in a crooked canter. Diagonal aids Aids: The rider applies the outside leg slightly further back from its neutral position, thereby activating the horse's outside hind leg, while adding the inside rein aid to indicate the direction of travel. This technique is later refined, first asking with the outside leg aid before adding the inside rein and a push with the inside seat bone. The refined sequence usually makes for a quicker and more balanced depart, and prepares the horse for use of the inside lateral aids. Purpose and Drawbacks: An intermediate step, this is the most commonly used sequence of aids by amateur riders, and is usually the one taught to beginners. The canter is generally straighter when asked in this way than when asked with the outside lateral aids, but still may not have the correct bend throughout