Sunday, August 1, 2021

The eighth pair of preludes and fugues in Book II of Bach’s Well-Tempered Clavier has a curious attribute: instead of being written in the key of E-flat minor (to match the preceding pair in E-flat major), it’s written in the “enharmonic”key of D-sharp minor. The difference cannot be heard or seen on the keys of the keyboard, but has only to do with how the music is written on the page: E-flat minor has six flats, while D-sharp minor has six sharps. Perhaps Bach wanted to challenge his pupils to be able to read in any key with equal fluency.