Reinhardt believed that if you tried to play in a manner that didn't agree with your physical makeup, then you would never be able to play up to your potential. There are all sorts of ways you can play, but he believed that "stepping on the toes of mother nature" would lead to failure. There are all sorts of systems and theories. Some believe that it's only the air that matters, and that using your air well will manifest itself in a good embouchure. Reinhardt believed in making sure the embouchure was working trouble free first, then would move on to improve the breathing.