J.S.Bach – Invention in Bb-major BWV 785

This is one of the 15 inventions from Bach with only two voices. Overall the piece sounds light-heartedly and soft, although in the centre of the piece Bach often uses deeper pitched notes, which creates a tune that sounds a bit more serious.

A score of the piece provided by the Petrucci Music library can be seen below. The theme that Bach works with for this piece ends in the centre of the first bar. (Starting on a Bb, ending on a D). Right after that it’s inversion is being played, where it has to be mentioned, that, at the end of the inversion Bach uses a third instead of a forth for the second last interval and a completely free ending for the last one.

If I haven’t miscounted (and I added the false entrances as well), I was able to find 16 “normal” subjects, of which eight were false entrances and 19 inversions with 13 of them being inversions for the right hand. In the left hand voice I found 21 subjects, including 13 false entrances and 11 inversions with 6 false entrances.

For the whole piece Bach uses a huge amount of false entrances of the theme, in both, original and inverted versions. In all of those cases its only the beginning motif (the first 4 or 5 notes) of the theme, that is being played.

Another thing I noticed concerning this piece in specific, is, that Bach uses 3 versions of a counterpoint (although all of them are mainly made up from arpeggios), but only throughout the first half of the piece. From bar 14 to the end either false or proper entrances of the theme or its inversion complete one another. (Whereas, at least until bar 15 the theme in the right hand is being played together with the theme in the left hand and vice versa with the inversions.