Wherever his fortunes took him, Bach was incredibly productive. In Anhalt-Cöthen (1717-1723) he flourished as conductor of the court orchestra and produced, among other works, orchestral pieces, concertos, and a dozen particularly amazing compositions, six for violin alone and six suites for cello alone.
The pieces for violin alone and cello alone are bold in ways that most other virtuosic string pieces are not. They demand not only unfaltering facility in matters of digital and rhythmic dexterity and preciseness of pitch, particularly in the multiple stoppings, but also the keenest musical insights and inner-ear sensitivity to implied polyphonic and harmonic textures.
The six violin pieces were designated by Bach three as sonatas, three as partitas. The sonatas as a group are more polyphonic than the partitas, each having a formal fugal movement, while the partitas are concerned with the dance movements common to the suites of the period.
The G-minor Sonata opens with an imposing Adagio whose grandeur, so miraculously set forth on the single violin, could not be enhanced if transcribed for a full symphony orchestra. The second movement fugue is one of those Bachian structures that grow to amazing proportions from an almost ridiculously brief and seemingly insignificant subject. A lovely and gentle Siciliana separates the fugue from the whirlwind that comprises the final movement — a presto, perpetual motion Baroque essay in violin virtuosity that will be as pertinent in 2020 as it was in 1720.