The Prelude (Andante, completed December 13, 1950) is based on a passacaglia. While a solemn bass theme is repeated ten times over 12 measures, contrapuntal melodies are woven, primarily in the highest voice. In the seventh repetition (from measure 73), the right and left hands invert, and the bass theme, which had previously served as background, vividly leaps to the foreground. Finally, even the melodic voices move to the lower register, accompanying the bass voice, and the music fades away in pianississimo, hinting at the first half of the fugue's subject.

The Fugue (4 voices, Allegro, completed December 15, 1950) is an active piece in 5/4 meter, forming a strong contrast with the Prelude. The subject contains many leaps and employs a natural minor scale lacking a leading tone, thus obscuring the tonality. Furthermore, frequent interruptions by rests bring an imbalanced sense of meter to the foreground of the piece. The countersubject, full of syncopation, also seems to promote the irregularity of the subject's rhythm. Both the complexity and character of the piece reach their climax in the middle section, after which they quiet down over a tonic pedal. Subsequently, a stretto where complexity returns leads chromatically to a conclusion with a Picardy third.