Despite its minor key, Bach's fourth invention has a
pleasant, swaying feel thanks to the smoothly rolling,
up-and-down contour of its top melody. The bottom picks
up the theme, but supports it with independent though
related material rather than mimicking it in strict
canon. Long, imposing trills intrude upon each part.
The "two-part" designation here applies not only to the
voicing but to the structure; the piece falls into two
halves, the second both a commentary on and
prolongation of the first.
Although originally composed for Harpsichord, I created
this arrangement for Viola Duet.