The “Hand & Heel” concept is iterated by the Duke of Newcastle, the Romanic school (including Californio Vaquero a la Ed Connell), as well as Francois Baucher and his disciples.
What is it? Different schools of equitation can make use of different aids and effects. The horse is especially sensate. He can feel a fly land on his leg, thus he is well capable of discerning the most subtle changes in pressure from our hands, legs, and weight.
But just because we can use such a range of effects as aids does not mean we necessarily should. In my opinion, it is pragmatic to focus the horse’s attention on the two most basic effects: the hand and the heels – in order to avoid confusion, and retain a highly mobile platform, predictable in range of circumstances – including the many situations which require that a rider displace his weight without implying new orders for the horse – i.e., opening a gate, straightening the saddle in motion, leaning over to adjust the spur, recovering a dropped rein, removing supplies from a saddle bag in motion, etc.
We want the horse operate within the “corridor” we create with our hand and our heels. It is a tunnel of sensations which create the only path he may take through the ether while I am astride. For my purposes, I want him to ignore everything else, and to keep doing what he was doing until he receives a clear directive to do something else.
If the order is ever unclear – if he becomes confused – the right answer is to keep doing the same thing until certainty resolves. There should never be negative repercussions for mere confusion. For this to be possible, the high school rider must have sufficient tact to discern malicious or stubborn resistance from innocent uncertainty.
The Hand: We want the horse perfectly attuned and highly responsive to the hand. He must accept it as an insurmountable barrier when it blocks, and listen to it attentively awaiting a change in vector or attitude. He should never attempt to compromise the boundaries indicated by directives associated with the hand.
The Heels: He must remain equally sensitive and attentive to the heels – mobilizing with enthusiasm when directed to do so, retaining his action by default, and demobilizing with equal enthusiasm as required. In general, we want him to ignore other possible cues, including shifts of weight, sounds, and sights.
The continuum of effects possible through the hand and heel should be ample to animate the finished horse. Artful training will produce a fidelity and lightness easily enabling all movements, and yet with aids so subtle as to be invisible to onloookers.
Done right, the horse will come to keep his energy invested precisely “between” these two aids, ever prepared to move his weight forward or back as indicated, while retaining his balance and movement – neither pushing into our hand (pulling – at all, even slightly), nor behind our leg (requiring ongoing or repetitive encouragement to go forward or mobilize – at all, even a little). Only thus is he truly “between the hand and heels” – an ideal underscored and described specifically and, more or less, identically by Newcastle at the dawn of “manege” in 18th century, and later by Baucher in the 19th century as a reaction to what, by then, had become the “old school” represented by Paris.
Importantly, this concept would become (and remains) an essential point of differentiation between the Baucherist and German flavors of high school riding: where Baucherism insists the horse remain balanced between the hand and heels (as does the vaquero school), the Prussian manner puts the horse ahead of the hand and behind the heels.