Structure and Character of the Goldberg Variations
“First of all, the theme. In the Aria we must follow the bass line, that is the foundation of the whole structure, all the variations are based on it. Second, there is the magic number of three. There are 30 variations, 10 groups of three. Each group contains a brilliant virtuoso piece, a gentle character piece and a strictly polyphonic canon. The canons are presented in a sequence of increasing intervals, starting with a canon in unison and ending in a canon in ninths. In place of a canon at the tenth (Variation 30) Bach gives us a quodlibet (what pleases), combining fragments of rustic folk songs with the ground bass. Thus the three main elements are physical, emotional and intellectual.
The tonality is consistently G major, with the exception of G minor in three variations (Nos 15, 21, 25). There are several dance-inspired movements: minuet, passepied, polonaise, gigue. G major is a sunny key. Bach gives us the sensation of the joy of life, the joy of movement. We performers have to transmit this to the listeners. In the great 25th variation, which Wanda Landowska has called “The Black Pearl”, we are suddenly in the world of the Saint Matthew Passion.
After the last variation the opening Aria returns, unchanged. However we are hearing it with new ears because of the experiences of the past 70 minutes.”