If you run straight towards steep hills or mountains on the horse, it will not ascend the slope. However, if you move left and right as you go forward, eventually you will hook certain areas which will let you get to the top of the hill without having to abandon your horse or find a road. If you try to come down from the hill while running at full speed, it will take damage until it eventually dies. However, if you move very slowly by only tilting the Analog-stick Forward a short distance, your horse or yourself will not take any damage. This is very useful for getting down out of mountains and similar locations, and you are not close to any roads or suitable paths.