Say you're running down hill and start to lose your balance. You run faster and bit more awkwardly right? What do you do? You slow down for a moment, catch your balance by bringing your upper body more upright and resume running down a hill a little slower and in balance. You just half halted yourself.
It's the same concept on your horse. The purpose is to rebalance your horse. You're trotting along, he starts to get strung out. You sit tall, close your legs around his sides asking him to step under himself more while using your hands to contain the energy momentarily in the outside rein.
Could you be more specific? Like as in the exact actions I would take to in-act a half halt. I'm asking for energy with my legs, but holding it back with the outside rein? I feel like if I just use one rein, he might turn! Please correct me if I am wrong!
A half halt is just like it says. Instead of halting, you pull back for a sec, give a leg cue. You want your horse to come back to you with power. Its also a cue of hey I am still here. Kind of thing. I use half halts a lot in driving. Its a cue to the horse to come back to my hands. It also gets there focus and mind back on to the task ahead.