The diagram below shows a left indirect rein (left), a direct rein (center), and a right indirect rein (right). For a left indirect rein, the rider’s left hand moves back and right hand moves forward, allowing the horse to turn its head to the left. For a direct rein, both hands are evenly placed and keep the horse’s head and neck straight. In a right indirect rein, the right hand moves back and the left hand moves forward, again allowing the horse to turn its head. If the hand to the outside of the bend does not move forward, the rider creates “clashing aids,” which is asking the horse to do something while preventing the animal from doing it. Nothing makes a horse more frustrated than when a rider clashes his aids.
An indirect rein position varies according to the degree of the bend. For example, when making a small circle, the horse would be bent more acutely, so the inside hand would be back more and the outside hand would have to move forward more to enable the horse to have a greater bend in its neck than if the horse were on a larger circle. The indirect rein can also be used very subtly. If a horse is spooking away from something on the outside of the arena, the rider can use a slight inside indirect rein, bending the horse toward the inside of the arena just a little, prohibiting the animal’s eyes from locking onto the spooky object. In this case, the bend would not be nearly so much as pictured above.