Piano Sonata No. 4 in B, Op. 25

Full Score

Audio rendering

Video

I have always found it a special challenge to compose music in the equal- tempered system, in which I do not customarily hear or think. If I am to restrict myself to such a small set of intervals, and forgo the essential distinctions between pairs of intervals that are enharmonically equivalent (e.g. between a major third and a diminished fourth), then either the music must be diatonic, or atonal, or there must be some kind of pitch-class game going on. Pitch-class games tend to wear out their welcome very, very quickly, which makes it hard to write "big" piano music. Accordingly, all of my piano works are comparatively brief; the second movement of this Sonata is the largest single form that I have composed for piano.

The pitch-class game in this Sonata is that only nine pitch-classes are used: B, C, D, D#, E, F#, G, G#, A#. This is the residue of the equal-tempered collection after the augmented triad A C# F is taken away. The set of nine is therefore symmetric around a triple axis, which is an academic way of saying that anything it can do on or around B, it can just as easily do on or around G, or D-sharp (E-flat). This permits just enough of a range of "modulations" to develop the forms of this work without plunging into monotony (at least, it is my judgment that I have not plunged into monotony).

The first movement ("Prelude") must be played as slowly as possible, given the acoustics of the instrument and the space. How slow is too slow? When the continuity of the softest passages threatens to be lost. The sample-library piano in the audio rendering has surprisingly poor sustaining power and the tempo is consequently substantially faster than one hopes would be possible in a live performance.

The second movement ("Toccata") bears much the same kind of oblique relation to sonata form as the Sonata's pitch-class set does to the diatonic collection. The "first theme" is a pair of tiny motives that are foreshadowed in the introduction and stated explicitly in bars 13 and 14. The "second theme" grows from a four-note motive first stated in the left hand in bars 53 -- 55. A codetta element appears first at bar 76 and in an expanded form at bars 82 and 83. Something recapitulatory starts happening at bar 147, although the development and recapitulation cannot be usefully distinguished. The "second theme" returns at bar 184 and the coda begins at bar 200.

The third movement is a travesty waltz, owing much to Shostakovich's affectionate (but very sharp-edged) parodies of Chopin. Its ending makes no sense, nor is it meant to; that is one way to define the difference between a parody and a travesty.