Externally applied forces (arpeggios)
J.M.’s lesson: an arpeggio going upwards in the left hand.
I sit to her left. Not very close. I don’t have to be on the piano bench, I can be on a nearby chair. As long as it is close enough to her body to be able to reach out with my arms and make contact with her left arm. My purpose is to use my arms to lead and guide her playing arm as it moves rightwards through the arpeggio.
Joe to J.M.: I am pushing your arm to the right, but my arm stays ahead of where your left hand is. It is actually trying to push your arm so that your hand is ahead (to the right) of where it needs to be situated to play the current note of the arpeggio. I’m pushing your arm ‘ahead’ of the progress of the arpeggio, giving your hand the feeling of having to constantly catch up with your arm.
I am really trying to create a vector- counter vector situation. For, while at the same time I am trying to have your hand experience how far to the right of its currently located position it is being asked to be, on the other side your job is to have your fingers nonetheless adhere to the surface of the keys that they are playing in such a way that is strong enough to resist the motion I am trying to apply.
However, the stronger your finger sticks to the note, the stronger I’ll push, until eventually the contest isn’t equal any more, and your hand unintentionally shifts / jumps to the right, faster than it could do so if you were using just internal muscles in your arm and body.
Were it not for your adhering to the current notes I might fling your arm helplessly off the keyboard, but because of your counter-vector, when your arm does move, it moves in a controlled manner but at a faster speed than at which it can normally travel. It is this extra momentum that allows the fingers to make all the difficult connections from one key of the arpeggio to the next, just beyond the limit of their pliability (such as the pliability of the thumb trying to pass under the rest of the hand).
If both forces remained absolutely equal, then we’ll never get to the next note of the arpeggio. You have to know just how long to hold onto the current before suddenly acceding to the force I’m applying. This ‘drama’ is re-enacted quite a number of times over the course of the full arpeggio.
For a moment your fingers and hand will fly ‘helplessly’ to the right until your fingers can reestablish contact with the keys. Like a mountain climber who lurches upwards or falls back lower until they can find a place to reestablish their grip.
The part of this procedure which has to do with staying on the key surface is also the part within you that wants each note to be sonorous. The part of the procedure which has to do with being moved off the key by the external force is the part of the procedure that creates the flow and dynamic sense of shape and motion of the arpeggio.
Ultimately you have to create both of these contesting forces by yourself from within your body alone. By my doing it to you first, your body ‘learns’ what it feels like when subjected to both pressures. After the learning period it can recreate that (combined) sensation on its own.
Whatever is done to you externally, it produces an inward sensation on the muscles within the body. When there is such an inward sensation, with a little effort of imagination we can recreate the exact same feeling, even without the physical cause from outside. And we can do this without without knowing just which muscles to try to move or by how much.
It is just a conscious (but complex), unified body state. It’s hard to form a static concept or visual image of how both of these parts act within you. On the one hand it may include the self same muscle enacting a synthesis of both forces. Or the other hand it may be the result of ‘tuning’ two different muscles together.
I do it to you first, so that your body can learn to “remember” and reproduce the sensations it felt when being pushed from the outside. At the same time your body must plant each finger on its note as if it would permanently stay there. You will create a dynamic equilibrium which then cedes to another dynamic equilibrium.
If we liken the process of playing the piano to that of acting in a play, then one part of this state will be enacting the character saying “come on already, it’s time move to the next note” while another part is enacting the role of the actor who says: “hold on, I’m not ready to come off the note yet, I’m enjoying the sound too much”. The result is a brilliant, smooth, and accurately executed arpeggio.
By having the teacher change their position relative to the student, including from which side of the student’s body the teacher locates their body, this procedure can be repeated just as easily for a downward arpeggio of the left hand (teacher is on the right side of the student’s body), an upwards arpeggio in the right hand (teacher is on the left again), and a downwards arpeggio in the right hand (teacher is back on the right). The distance from the torso of the student has to adjusted in response to whether one is pushing the student’s arm nearest the side from which the teacher is pushing, or pushing the student’s arm that is on the other side of their body from the side from which the pushing is occurring.
In most cases that involve difficult technical situations on the piano, it’s all about vectors and counter vectors*: forces in one direction, countered by forces in other or opposite directions.
* A vector is a combination of a measurable direction and a measurable quantity . “I am walking northwards at 3 miles per hour”.