WTC I C p :  (I.E. book one of the Well Tempered Klavier, C Major, the prelude):

What is controllable and what is not?

A.B.’s playing of the first fugue of book one of the Well Tempered has improved by leaps and bounds.  Due to the quality of his mind he can contemplate and wonder at the amazing things, small and large, going on in the piece.

Here is what arose on Thursday, May 16, at our latest lesson.

The first finger should move in a plane so that it goes directly towards the body as an extension of the longitude of the key which it is on, and not as the thumb will be wont to do: which is to move sideways so as to execute a more natural motion.  The same for the pinky.  There is a tendency, at least in my-sized hand, to have the pinky and the thumb move towards each other when depressing their keys. But the tip of the pinky as well as the thumb should move in a line perpendicular to the piano keyboard and along the longitude of the key.  Again, this is hard, because the hand is spread for the octave, with the pinkie having moved sideways to the right (if the right hand) when the hand is open for the octave.

The muscles that enable the pinky and thumb to move along the longitude of the keys, which results in their greatest degree of control of the depression of the keys, in other words to be able to move in these constrained directions, requires first, in the case of the (right) pinky an extreme flexion of the third knuckle, down and aimed to the right as it moves in the direction of the body, aided also somewhat by a flexion in the right side of the wrist.  In the case of the (right) thumb it can practice its motion by slowly tracing  over a line on a desk which is drawn perpendicularly to the front right-left side of the desk.  The third knuckle of the thumb, where it attaches to the wrist, is prominent in keeping the thumb congruent with this line.  As the motion is made the thumb is always fighting the desire to move outwards away from the second finger.

#1

To even out the touch on a series of notes, especially if the sequence of fingers are adjacent, it is best to precede the execution of the separate notes by play a cluster made up out of all the notes.  The trick is that when you now segue to the notes played sequentially, you retain in your hand and in your body the feeling that each of the five fingers is playing each individual notes, and not that only one finger plays at a time.

Debussy: First Arabesque: the conclusion to the first of the three main parts.

What is the main melody that one should bring out during the passage that concludes the first part and leads to the middle part of the piece.  A.J. said that when I played it I was doing something that that made it work sound-wise but he couldn’t figure out what I was doing. He assumed that I was emphasizing one of the three layers of melodic motion embedded in the passage. I said, it is more complex than that.  There are three different things going on, but no one of which, by itself, is a significant melody.  It is only in the complex ways the three interact that causes the positive quality that I think you noticed.  The rising quarters in the rh form a melody of no great significance.  The cello-like melody in the left hand does have a singing melody, but by itself it doesn’t seem accomplish that much, as well. Then there are triplets.  Are they important or not? The real question is how to bring them together in a complex fusion that makes the passage glow and excite.