No one person "invented" NH and no one trainer can claim that it is something that is exclusively theirs.
One of the earliest examples of NH is in the famous story of Alexander the Great and Bucephalus.
No one could tame or ride the big black horse and he was fated for a short life. But young Alexander could see something that escaped the notice of the finest trainers of the day. The horse was afraid of his own shadow. So facing the horse into the sun he quickly mounted and rode the horse.He named the horse Bucephalus and if followed Alexanders throughout his life.
The point of the story is that this is what NH is. Not gagets or one person saying their method is better or worse than anothers.....just simple observation and acting in a logical maner to understand why a horse acts in a certain manner.