Rotation Principle ...my gosh thats pretty simple....Matthay or no Matthay.
R.H: five finger straight on ..1,2,3,4,5, the rotation is always away from the finger last played..being aware of this and using this principle can help you direct the energy to acheive the result of evenness without excess tension.
Beginning is a little trickey BECAUSE you will rotate TOWARD the thumb ..the energy is directed there frist...THEN away from the thumb toward the 2nd finger ..rotation is toward it and then toward 3, toward 4 and finally toward 5. There are still photo's of Dame Myra Hess playing the last note of a phrase and you can see her hand rotated to that 5th finger..almost standing on end..Thats an extreme example..but you get the idea. Why not use all we know to help that 5th finger in doing its job...with utmost control of course.
Play an octave alternating the notes Alberti bass style. You may choose to use only finger action in some cases or you may choose to use forearm rotation...whichever you CHOOSE to do according to what you want the sound to be like. Forearm rotation: whichever finger you choose to start with you will rotate TOWARD that finger. One way Matthay used to demo this was you grasp a dowel or yardstick about in the middle. Then extend your hand and forearm in front of you ..hand palmside down. Then move the dowel or yardstick to one side and the other keeping it in a horizontal position. ..Done properly this will give you the feeling of forearm rotation.
The deal is..being aware of these physiological possibilites and USING them when you need them and when they HELP you to play the passage more easily and correctly.
Topic: Let Eunice Tell You About Rotation