Arpeggios: hand stretch (with nikkyo) vs. displacement

[nyquist]

I am requesting advice on how to play a section of Debussy's Arabesque No. 1.  In this piece there is a descending series of left-hand up-and-down arpeggios that span about a twelfth each.  (Each arpeggio has four different notes organized in two triplets: something like: C4, E4,  B4; E5, B4, G4.)  My hand is large so I could play this by stretching and leaving the hand placed for each arpeggio and displacing the hand for the next one---with perhaps a bit of "cartwheeling" (to use Chang's term).  This requires setting the span of the hand along the keyboard, which means that my forearm and my hand are not aligned, particularly when the hand is above middle-C (in Aikido-speak, I am doing "nikkyo" to myself).

 Alternatively, if I keep the hand and forearm aligned, I cannot span the arpeggio and need to move the hand up and down for each arpeggio---the forearm is at an angle to the keyboard.  In the first version, I can keep "finger legato".  In the second version, I feel I am playing the piano almost as a marimba: depress each key to make the note sound and keep motoring to the next note with the whole hand moving (the sustain is down, of course).

Hope this all makes sense.  Advice, alternatives, suggestions much appreciated.

Nyquist

[Hmoll]

  (in Aikido-speak, I am doing "nikkyo" to myself).

 

Sounds interesting. I always wanted to see someone be Uke and Nage simultaneously.

Seriously, I think the problem might be you are thinking of the arpeggio as a hand position, and that's causing you to stretch you fingers, and possibly contort your wrist when you don't need to.
I would practice it by using a separate wrist rotation on each note, walk each finger to the next note, be careful not to stretch to reach the next note - it's really not needed. Look at your hand as you're doing this. When you get to your thumb note, your 5th finger should not be sticking out (stretching), it should have followed your hand along the direction of the thumb and your hand should have a more closed than open position.