So what exactly is meant by playing from the elbow as opposed to playing from the shoulder? How and why does the right one work, and why does the wrong one not work? The single most important factor to understand in relation to the problem of piano technique is the physical law of action and reaction - Newton's Third Law of Motion: "For every action there is an equal and opposite reaction". As applied to piano playing what Newton's law means is that when a finger depresses a key the amount of force used to perform this action is met by an equal amount of force acting in the opposite direction - a reaction. The reaction of one finger playing one note is not very great, but when playing a number of consecutive notes at high speed or when playing big loud chords, the amount of force produced in reactions is very great and must be contained or eliminated by the rest of the playing mechanism backing up the actions of the fingers and hands. I will explain why in the following section. Teachers, writers and even pianists who advocate finger exercises and scales, etc, "in order to strengthen the fingers" - in isolation - and without any consideration of the demands of action and reaction, that is, without consideration of the necessity of providing a solid basis for fingers to act against, and without consideration of the necessity for elimination or containment of the reactions caused by the actions of the fingers and hands in overcoming the resistance of the keys - indeed without even being aware of any issue concerning these matters - are missing the most essential element of the enquiry. That enquiry must be predicated upon scientific terms, whereas most teachers concentrate on the artistic end to be achieved without any understanding of the means of achieving that end. Piano playing requires a combination of artistic expression and physical, bio-mechanical, physiological activity - what we call technique. But the scientific, bio-mechanical elements must be put in place first - or at least at the same time as the artistic; not afterwards, because without technique no artistic expression will ever be possible. Indeed it is true to say that although technique alone will not make one an artist, it will get you about 90 per cent of the way there. And the more technique you have, the better and more artistic your playing will sound.