Originally for solo flute and string orchestra, the flute part is given here (transposed down two octaves) to the top cello voice. The second cello part is unchanged from Bach’s original. For a perfectly democratic distribution of both the difficulties and the protagonism, the solo part can be shared by simply swapping voices (lines) at the repeats. The easier version is simply transposed down one tone (into A minor) but apart from that it is identical to the “harder” version.
Bach starts the piece with an upbeat. In my arrangement I have taken the liberty of displacing the beat (the upbeat is now the downbeat) so as to make it read as it actually sounds. My apologies to Bach.