As we progress through the collection, we continue to find different styles and architectures in each variation. Variation 10 was named a “Fugetta” – i.e., a small, less developed fugue. It’s set to four voices, with a four-bar theme that starts on the bass, moves to the tenor in bar 5, then to the soprano in bar 9, and finally to the alto four bars later. The second half sees the theme introduced in the soprano first, then alto. Both voices are accompanied by the bass until it, too, gets the subject in bar 25, with the tenor’s entrance saved for last.

Variation 11 is structured as a two-part invention in 12/16 meter, with virtuosic scales and arpeggios that span a wide range in both voices, creating the need for two manuals as the parts intersect.

Variation 12 is the next canon in the series, this one at the fourth, one bar apart and by inversion. The two canonic voices are supported by a bass line that moves mostly in quarters, clearly enunciating (at least for a few bars!) the bass line that underpins the entire composition.

The Dutch harpsichordist Bob van Asperen recorded this performance of the Goldberg Variations in 1990, in the Schloss Charlottenburg, Berlin.