[1.III.5.5] Arpeggios (Chopin, Cartwheel Motion)
Playing arpeggios correctly is technically complex. This makes arps particularly suitable for learning some important hand motions, such as thrust, pull, and the "cartwheel motion". "Arpeggio", as used here, includes broken chords and combinations of short arpeggic passages. We shall illustrate these concepts here using Beethoven's Moonlight Sonata (3rd Movement) for the thrust and pull, and Chopin's Fantaisie Impromptu (FI) for the cartwheel motion. Recall that suppleness of the hands, especially at the wrist, is critical for playing arps. The technical complexity of arps arises from the fact that in most cases, this suppleness must be combined with everything else: thrust, pull, cartwheel motion, and TU or TO. One note of caution: the Moonlight is difficult because of the required speed. Many Beethoven compositions cannot be slowed down because they are so intimately tied to rhythm. In addition, this movement requires a minimum reach of a 9th, comfortably. Those with smaller hands will have much more difficulty learning this piece than those with adequate reach.
Let's first discuss how to play TO arps. Arps extending over several octaves are played TO just like long scales. Therefore, if you know how to play TO scales, you know, in principle, how to play TO arps. However, the method of playing TO arps is a more extreme example of the TO motion than for scales and therefore serves as the clearest example of this motion. We noted above that the easiest TO motion is that used in playing chromatic scales (1313123131312 ... for the RH). The chromatic TO motion is easy because the horizontal motion of the thumb is small. The next slightly more difficult motion is that for playing the B major scale. This TO motion is easy because you can play the entire scale with flat fingers so that there is no collision problem with the passing thumb. The next in difficulty is the C major scale; it is more difficult because all the fingers are crowded into the narrow white key area. Finally, the most difficult motion is the TO arp in which the hand must move rapidly and accurately. This motion requires a slight flex and flick of the wrist, sometimes described as a "throwing" motion. The nice thing about acquiring the TO arp motion is that, once you learn it, you simply have to make a smaller version of the same motion in order to play the easier TO motions.
Because arps jump over several notes, most people spread the fingers to reach those notes. For fast arps, this is a mistake because spreading the fingers slows down their motion. The key method for fast arps is to move the hand instead of spreading the fingers. If you move the hand and wrist appropriately, you will find that it is not necessary to spread the fingers. This method also makes it easier to relax.
The Cartwheel Method (Chopin's FI). In order to understand the cartwheel motion, place your left palm flat on the piano keys, with the fingers spread out as far as you can like the spokes of a wheel. Note that the fingertips from pinky to thumb fall on an approximate semi-circle. Now place the pinky above C3 and parallel to it; you will have to rotate the hand so that the thumb is closer to you. Then move the hand towards the fallboard so that the pinky touches the fallboard; make sure that the hand is rigidly spread out at all times. If the 4th finger is too long and touches the fallboard first, rotate the hand sufficiently so that the pinky touches the fallboard, but keep the pinky as parallel to C3 as possible. Now rotate the hand like a wheel counter clockwise (as viewed from above) so that each successive finger touches the fallboard (without slipping) until you reach the thumb. This is the cartwheeling motion in the horizontal plane. If your normal reach is one octave with your fingers spread out, you will find that the cartwheeling motion will cover almost two octaves! You gain extra reach because this motion makes use of the fact that the center three fingers are longer than the pinky or thumb. Now repeat the same motion with the hand vertical (palm parallel to fallboard), so the fingers point downwards. Start with the pinky vertical and lower the hand to play C3. Now if you roll the hand up towards C4, (don't worry if it feels very awkward), each finger will "play" the note that it touches. When you reach the thumb, you will again find that you have covered a distance almost twice your normal reach. In this paragraph, we learned three things: (1) how to "cartwheel" the hand, (2) this motion expands your effective reach without making any jumps, and (3) the motion can be used to "play" the keys without moving the fingers relative to the hand.
In actual practice, cartwheeling is used with the hand somewhere between vertical and horizontal, and the fingers will be in the pyramid position or slightly curved. Although cartwheeling will add some keydrop motion, you will also move the fingers in order to play. We apply this method to the LH broken chords of Chopin's FI. In section III.2, we discussed the use of cycling to practice the LH. We will now add the cartwheel motion to the cycling. Cycle the first 6 (or 12) LH notes of bar 5 (where the RH first joins in). Instead of just translating the hand sideways to play each note, add the cartwheeling motion. If you position the hand almost horizontally, then practically all the keydrop must be accomplished by finger motion. However, if you raise the hand more and more towards the vertical, the cartwheeling motion will contribute more keydrop and you will need less finger motion to play. Cartwheeling is especially useful for those with small hands because it automatically expands the reach. Cartwheeling also makes it easier to relax because there is less need to keep the fingers spread widely apart in order to reach all the notes. This motion also releases the tension in the wrist because you can't cartwheel with wrist tension. These reductions in stress make the hand more supple. You will also find that your control increases because the motions are now partly governed by the large motions of the hand which makes the playing less dependent on the motion of each finger and gives more uniform, even results.