Brandenburg Concerto No. 6 in B flat major, BWV 1051, first movement. Title on autograph score: Concerto 6to à due Viole da Braccio, due Viole da Gamba, Violoncello, Violone e Cembalo [no tempo indication, alla breve] (usually performed at Allegro or Allegro moderato)

Bach scored the sixth concerto in this set for a combination of string instruments that is unusual in several ways. Firstly, it features the low sounding members of the string family -no violins. Secondly, the solo instruments -two violas da braccio and a cello -and the accompanying tutti instruments -two violas da gamba, violone, and harpsichord - are unusual instruments for Bach. Finally, at the beginning of the first movement the solo violas play in close canon, only an eighth note apart, like a closely argued conversation. The canonic writing becomes even more complex as the movement goes on. The choices