The Mountain and the Tree

I got into the habit of riding with one hand on the reins more or less by default quite early on, since I did most of my learning on hacks rather than in the arena, riding along comfortably. Well, that and dressage training, learning to give directions with almost no movement, just a shift of your weight. So the trick is to keep the reins taut and just angle your wrist a little, shifting your weight - thinking leftwards, is the best way I can describe it. Maybe it's one of these things you learn to do unconsciously.