Suppling the forehand.—The hind quarters having been drilled by the foregoing work, we must promptly train the forehand in order that both ends of the horse shall be in harmony as regards mobility and suppleness.
Shoulder in.—"Shoulder in" is the starting point in forehand suppling; this exercise furnishes the means of bending the forehand and spinal column and of training the forelegs to cross each other easily. La Guérinière says:
This lesson produces so many good results at once, that I consider it the first and the last to be given to the horse.
"Shoulder in" is obtained in the following manner:
Marching on the right hand, open the right rein as in changing direction to the right, and press the left rein upon the neck. Close the right leg to push the mass from right to left and slip the left leg behind the girth to restrict as much as possible the swinging of the haunches.
The support of the left rein is indispensable in order to keep the proper balance of the shoulders—that is, to prevent the weight of the right shoulder from plunging heavily upon the left shoulder.
The horse's head must be firmly held between the two reins, otherwise the exercise would become a lateral flexion of the neck and would do more harm than good.
The bending of the horse's body should not be overstrained. For example, it is perfect if, on the right hand, the left front foot and the right hind foot make tracks on a line obviously parallel to the wall of the riding hall.