Half halts are a way that the rider can re-balance your horse. But it’s a term that gets tossed around frequently without adequate explanation. As a result, many people think they are doing a half halt but don’t know why and don’t do it correctly. Much of the confusion probably lies in the use of “halt.” It should be a called the “balance” because you are not stopping your horse, you helping your horse shift it’s balance back onto it’s haunches and lighten it’s forehand but without losing impulsion.
Jane Savoie gives one of the best explanations that I’ve heard on how to perform a half halt and what benefits it brings.