I was touched by this excellent essay on the topic of Losgelassenheit, which is one of those long German words that needs a paragraph to translate. Well, here are several paragraphs which do a great job of it.

Here’s a quote to entice you to read the rest:

“Losgelassenheit, we were taught, is the most important stage in the training of the horse.

This “state” of deep relaxation allows the horse to perform movements later, without damaging his body, burning his nervous system or lose trust in the rider. It is this stage that prevents the loss of the natural paces, bad tension in the muscles and which also assures that we have the full attention and participation
of the horse. If a horse shies, he is not losgelassen or has lost his losgelassenheit. Same if he loses balance or is irregular DAP etc, in his gaits: he lost this central calmness.”