Most of Bach's surviving compositions in this category date from the years in Cöthen. Many similar pieces have undoubtedly been lost; others once attributed to Bach are now regarded as doubtful or spurious. For an up-to-date list of the authenticated works, see the "J.S. Bach" article in New Grove.
Bach's solo music for violin, cello viola da gamba, flute and lute may normally be classified either as sonatas (usually following Corelli's four-movement design) or as suites (sometimes called partitas, each comprising a set of dance movements). Some are for a single instrument without accompaniment: six sonatas and partitas for violin (BWV 1001-6), six suites for cello (BWV 1007-12), a partita for flute (BWV 1013), and seven works for lute (BWV 995-1000, 1006a). These works are very idiomatic for the particular instrument, and skillfully create harmonic and contrapuntal effects despite the absence of an accompaniment. Other pieces are for a solo instrument, with continuo: two sonatas for violin (BWV 1021, 1023), and two sonatas for flute (BWV 1034, 1035). Still others are for a solo instrument, with a written-out harpsichord part: six sonatas for violin (BWV 1014-19), three sonatas for viola da gamba (BWV 1027-29), and two sonatas for flute (BWV 1030, 1032). In these sonatas with harpsichord obligato, Bach often achieves a trio texture, by assigning two parts to the right and left hands respectively of the harsichordist, and a third part to the other instrument.