[1.III.1.3] Legato, Staccato
Legato is smooth play. This is accomplished by connecting successive notes – do not lift the first note until the second one is played. Fraser recommends considerable overlap of the two notes. The first moments of a note contain a lot of "noise" so that overlapping notes are not that noticeable. Because legato is a habit that you must build into your playing, experiment with different amounts of overlap to see how much overlap gives the best legato for you. Then practice this until it becomes a habit so that you can always reproduce the same effect. Chopin considered legato as the most important skill to develop for a beginner. Chopin's music requires special types of legato and staccato, so it is important to pay attention to these elements when playing his music. If you want to practice legato, play some Chopin. The basic keystroke is absolutely necessary for legato.
In staccato, the finger is bounced off the key so as to produce a brief sound with no sustain. It is somewhat astonishing that most books on learning piano discuss staccato, but never define what it is! The backcheck is not engaged for staccato and the damper cuts off the sound immediately after the note is played. Therefore, the "hold" component of the basic keystroke is absent. There are two notations for staccato, the normal (dot) and hard (filled triangle). In both, the jack is not released; in hard staccato, the finger moves down and up much more rapidly. Thus in normal staccato, the key drop may be about half way down, but in hard staccato, it can be less than half way. In this way, the damper is returned to the strings faster, resulting in a shorter note duration. Because the backcheck is not engaged, the hammer can "bounce around", making repetitions tricky at certain speeds. Thus if you have trouble with rapidly repeated staccatos, don't immediately blame yourself -- it may be the wrong frequency at which the hammer bounces the wrong way. By changing the speed, amount of key drop, etc., you may be able to eliminate the problem. In normal staccato, gravity quickly returns the damper onto the strings. In hard staccato, the damper is actually bounced off the damper top rail, so that it returns even more quickly. The hammer shank flex can be negative in staccato, which makes the effective mass of the hammer lighter; thus there is a considerable variety of tones that you can produce with staccato. Therefore, the motions of the hammer, backcheck, jack, and damper are all changed in the staccato. Clearly, in order to play staccato well, it helps to understand how the piano works.
Staccato is generally divided into three types depending on how it is played: (i) finger staccato, (ii) wrist staccato, and (iii) arm staccato, which includes both up-down motion and arm rotation. (i) is played mostly with the finger, holding the hand and arm still, (ii) is played mostly with wrist action, and (iii) is usually played as a thrust, with the playing action originating at the upper arm. As you progress from (i) to (iii) you add more mass behind the fingers; therefore, (i) gives the lightest, fastest staccato and is useful for single, soft notes, and (iii) gives the heaviest feeling and is useful for loud passages and chords with many notes, but is also the slowest. (ii) is in between. In practice, most of us probably combine all three; since the wrist and arm are slower, their amplitudes must be correspondingly reduced in order to play fast staccato. Some teachers frown on the use of wrist staccato, preferring mostly arm staccato; however, it is probably better to have a choice (or combination) of all three. For example, you might be able to reduce fatigue by changing from one to the other, although the standard method of reducing fatigue is to change fingers. When practicing staccato, practice the three (finger, hand, arm) staccatos first before deciding on which one to use, or on how to combine them.
Because you cannot use the arm weight for staccato, the best reference is your steady body. Thus the body plays a major role in staccato play. Speed of staccato repetition is controlled by the amount of up-down motion: the smaller the motion, the faster the repetition rate.