The Sonata in F sharp minor H37 (Wq52/4) dates from 1744. The most remarkable movement is the opening Allegro, built on a contrast between fantasia and lyric passages. The movement opens with rapid passagework in semiquaver triplets. After the first four bars, which are grounded by irregularly spaced accented notes in the bass, Bach confuses the rhythm through metric displacement of the lowest notes within rising scalic or arpeggiated passages. Rather than reinforcing the beat, these low notes are often placed on the second semiquaver of a triplet. The result is rhythmic instability, resolved only by the ultimate arrival on a long note at the end of the phrase. Bach follows this fanciful opening with a contrasting galant theme accompanied by steady repeated quavers. Although the movement as a whole is in a standard rounded binary form, within each section the fantasia and lyrical elements alternate, sometimes in short fragmentary phrases.
In comparison to this unusual opening movement, the following Poco andante, in D major, is a study in restrained elegance. Here Bach evokes a trio sonata, with two treble voices in imitative texture set over a steady bass in quavers. The finale is again in binary form featuring dotted rhythms and occasional sudden rests setting off dramatic harmonic progressions. In one case, the rest lasts for an entire bar, placing in relief a diminished third in the bass, soon followed by still another silence preceding a diminished triad. More restrained than some of his other early finales, this movement balances continuity with rhetorical irregularities.
from notes by Leta Miller © 2012
University of California, Santa Cruz