The Chromatic Fantasia and Fugue is an extravagant work of virtuosity and bold harmonic structure. It is an extraordinary piece - large, sprawling, emotional, and unique in its character compared to the rest of Bach's music. The title of the piece comes from either the fugue’s chromatic melody, or from the startling modulations in the Fantasia. Either opinion is equally acceptable and debated.
Bach composed only a few “fantasies” - a type of prelude usually preceding a fugue. The Fantasia is highly virtuosic and similar in form to the toccata, English fantasy, and the canzone, in that it consists of alternating sections of differently textured music. The English fantasy differs from Bach’s fantasies because it does not contain any free, improvisational sections. And unlike the Italian canzone, Bach’s chromatic fantasy does not include sections of imitative counterpoint.
The Fantasia consists of three main sections: the first (0:00) being a true prelude, the second (3:38) a recitative-like section, and the third (4:58) a mixture of the two. Some scholars, however, categorize the extensive arpeggio part preceding the recitative as a separate section in itself. The first section consists of technically demanding toccata-like passagework. Conversely, the recitative that follows is musically challenging, requiring extreme emotional sensitivity. And the third section combines the two elements in a virtuosic drive to the end.
The fugue begins in a strict style but gradually loosens, revealing elements of the fantasy. It opens with a long and complex semitonal subject. The fugue has three sections with eleven entrances of the fugal theme. Every entry of the theme contains an element of uncertainty, yet each seems to be anticipated by the previous one. The first section stays mostly in d minor, while the second section modulates as the theme is introduced in distantly related keys. The third section again returns to d minor and ends with bravura passage work, scales, and “organistic” octave doubling in the bass, not unlike the closing of a toccata. Compared to the fugues of The Well-Tempered Clavier, this fugue is treated much more freely.
0:00 - Fantasia
6:54 - Fugue
description adapted from:
spot.colorado.edu/~korevaar/ch...