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Section 30.8 Fugue Analysis

We will now turn to analysis of fugue. Let us set out definitions first.

  • A fugue is a contrapuntal composition whose form features sections called expositions and episodes

  • A fugue exposition is a section that contains at least one full statement of the subject of the fugue.

  • The fugue subject is the primary melodic idea and is stated by each voice in turn in the first exposition.

  • The response, called “answer” in some texts, is the subject intervallically altered to start in the original key before modulating to the dominant. Notice that the third note of the subject in the example below descends a perfect fourth to the fourth note. In the response in measure 3, the third note descends a perfect fifth to the fourth note.

  • An episode is a section that does not contain a full statement of the fugue subject, but instead develops the subject or other prominent ideas through fragmentation and sequencing.

Here is the first exposition of Fugue 2 in C minor in Book I of the J.S. Bach’s Well-Tempered Clavier. In the first exposition of a fugue, all of the voices state the subject at least once. It is important to note that a response is considered equivalent to a subject because the intervallic alterations are so minute.

Figure 30.8.1. First Exposition of Fugue 2 in C minor from WellTempered Clavier, Book I (BWV 847)
  • The bridge, if it occurs, is a brief modulatory passage that only happens within the first exposition, usually to connect the response to the subsequent subject statement.

  • A countersubject is counterpoint that consistently accompanies each occurrence of the subject. “Countersubject 1” is in the alto voice in measure 3 and in the soprano voice in measure 7. The alternative to using a countersubject would be for a composer to write different accompanying counterpoint (labeled as “CTRPT” in the examples) each time a subject is stated.

Within the bridge (bar 5 in the example above), we see motivic fragmentation of the subject (“subject head”). Subjects, responses, and countersubjects can be fragmented into head motives and tail motives in episodes in fugues. In this fugue, we will see the subject, countersubject 1, and countersubject 2 fragmented.

Below is the first episode, which contains motivic fragmentation of the subject and countersubject 1.

Figure 30.8.2. First Episode of Fugue 2 in C minor from WellTempered Clavier, Book I (BWV 847)

Below are the second exposition, the second episode, the third exposition, and the third episode.

Figure 30.8.3. J.S. Bach, Fugue 2 in C minor from WellTempered Clavier, Book I (BWV 847)

In the four systems below, we see the fourth exposition, fourth episode, and final exposition, which includes two subject statements separated by cadential material.

Figure 30.8.4. J.S. Bach, Fugue 2 in C minor from WellTempered Clavier, Book I (BWV 847)

In homework and on the test, you will be asked to analyze a fugue with regard to expositions (including the bridge, if it occurs), episodes, subjects, responses, countersubjects, and motivic fragmentation.