These three separately transmitted sonatas hide some attribution problems. BWV 1020 (the Sonata in g minor) is quite possibly by Bach’s son Carl Philipp Emanuel, and today is mostly played on the flute even though the sources assign it to the violin. It is interesting, however, that d1 is the lowest melodic note in the piece, which might mean that it is a flute arrangement of a violin sonata.

The other two sonatas also stand on an uncertain footing in regard to their sources. On the other han...