On the face of things, it might appear that the halt is a simple thing to accomplish...after all, all the horse has to do is stand still, right? In the world of dressage however, that is not an accurate statement. Gustav Steinbrecht said that a good halt is at the foundation of all the upper level movements. I found this statement very surprising! FEI trainer Volker Brommann said that in order to have a good halt at any level, you must have a foundation of trust and understanding. Hearing these statements may begin to clarify that the halt is not so simple.
In a good halt in dressage, the horse should be straight and square, with the weight borne evenly on all four legs. It's not uncommon for the horse to shift onto the forehand, rest a hind leg, brace against the bit, and other actions that mar a perfect halt. In more than one dressage show my little horse Raz would glide beautifully into the final halt, and just as I was about to breathe a silent " YES! Perfect halt!" he'd shift his weight to the left, and step his left hind leg off to the side.
So true! It's more difficult than it may seem to get them to step under as they are coming into the halt! Less than ideal conditions are a great time to perfect this movement!