The term “effortless mastery” is actually redundant because masteryis the effortless execution of music. It does not refer to how many things one can do but rather the quality with which one does anything. If something can be done perfectly, every time, without thought, it is said to be mastered. At performance time, music plays itself while the musician Mastery is playing whatever you’re capable of playing, every time, without thinking. That is why the great ones can do what they do every night without faltering. It is that easy.