Bull Hunter by Max Brand

The cut proved, as he had said, to be a small thing; but it turned out that Diablo was far from won. He was haltered and he would carry Bull bareback. The saddle was quite another affair. So Bull returned to the idea of the barley sack, with gradual additions. On each side of the sack he attached hanging straps. Diablo snorted at these and tried them with his teeth. They reminded him vaguely of the swinging stirrups that had so often battered his tender sides. He discovered that the straps were not alive, however, and were not harmful. And when their length was increased and an uncovered stirrup was tied on each side, he gradually became accustomed to these also. The next stage was passing the straps under his belly. They were tied there loosely, the circle was completed, and Diablo, examining them critically, found nothing wrong. Then, a dozen times in a single evening, the straps were drawn up, tighter and tighter, until they touched him. At this he became excited, and it required all the resourcefulness of Bull to quiet him. But in three days the barley sack and its queer-looking additions had been changed for a true saddle -- with the cinches drawn up tight enough for riding. And this without eliciting a single bucking spasm from Diablo!

Not even to Tod did Bull Hunter impart his great tidings. He had not yet climbed into that real saddle; Diablo had not yet heard the creak of the stirrup leathers under the weight of his rider. Indeed, there was still much to be done before the happy day when he saddled the black stallion and took down the bars of the corral gate and rode him out. And rode him without a bit! For on the point of steel in the mouth of Diablo, Bull Hunter knew that the horse would be against it resolutely. So he confined himself to a light hackamore alone. That was enough, for Diablo had learned to rein over the neck and stop at the slightest pull of the reins.