Fingering

Anatomy

The simplest anatomical principle is the maximum stretch between two fingers. An average pianist might have the following maximum possible spans: 15 semitones (a minor tenth) between the thumb (1) and little finger (5), 12 semitones (an octave) between 1 and 3, 10 (m7) between 1 and 2, 5 (P4) between 2 and 3, and so on. These spans automatically limit the number of possible fingerings for a given passage, but extreme spans may also be uncomfortable, so pianists may avoid them if possible. The maximum comfortable stretch between 1 and 5 might be 13 semitones; between 1 and 3, 10; between 1 and 2, 8; and between 2 and 3, 3. These numbers may depend on whether keys are black or white. Maximum stretches also include limitations in the ability to pass the thumb under other fingers. A pianist may be able to play an interval of 4 semitones when passing the thumb under the middle (3rd) finger in non-legato, and only 2 in legato.

Motor Control

Some combinations of fingers are easier to control than others, or can be moved independently more easily than others. The strongest and most controllable fingers are thumb, index, and middle finger, so for fast passages covering small spans these fingers tend to be preferred. The most obvious limitation of the human hand in this regard is the limited ability to lift the 4th (“ring”) finger relative to neighboring fingers 3 and (to a lesser extent) 5. So pianists tend to avoid placing 4 on black—especially if the preceding or following tones are white. Another consequence is that direct transitions between 3 and 4 are avoided in both directions, especially if 3 is on white and 4 on black, and especially if the transition is repeated (as in a trill or other ornament). Alternations of 4 and 5 are less difficult, but they are avoided for the additional reason that both 4 and 5 are considered generally weak (slow, more difficult to coordinate or control force); trills between 4 and 5 are difficult to play quickly without other muscles becoming tense. That reflects another general principle of fingering choice based on motor control, namely that fingerings should be chosen to facilitate relaxation of muscles that are not needed in a given moment.

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