The countersubject
The countersubject is the line that a voice plays against the answer right after stating the subject, and which then regularly accompanies the following entries. If it always returns (even transposed), we speak of a fixed or "regular" countersubject; if it changes, of free counterpoint.
Characteristics of a good countersubject:
- Rhythmic contrast: if the subject has long notes, the countersubject moves; if the subject runs, the countersubject holds.
- Contrast of profile: it goes in the opposite direction (contrary motion) at key points.
- It is written in invertible counterpoint at the octave with the subject, because it will have to stand both above and below.
- It has an identity of its own too, but weaker than the subject's, so the listener does not confuse the roles.
In fugues with two countersubjects (like the Fugue in C minor BWV 847) subject and countersubjects are in triple counterpoint: the three lines can stand in all six arrangements.
The codetta (or bridge)
Between the end of the answer and the next entry of the subject, a few beats or a bar are often needed to return from the dominant to the tonic or to let the voices "breathe": this is the codetta. It is short, usually built on fragments of the subject.
The episodes
Episodes (or divertimenti) are the sections without complete entries of the subject. They have three functions:
- Modulate: they lead from the key of one entry to that of the next (relative, dominant, subdominant, supertonic…).
- Contrast: they lighten the texture (often one voice rests) and change the color before the subject returns.
- Develop: they work on fragments of subject and countersubject, almost always in sequence.
Typical episode techniques:
- Sequence by descending fifths (for example Am–Dm–G–C–F in C major), with a fragment of the subject repeated at each link.
- Fragmentation: you take the head or tail of the subject and repeat it, shortening it.
- Close imitation between two voices on a fragment.
- Voice exchange: in the fugue in C minor BWV 847 some episodes return with the parts inverted, almost like internal "ritornellos".
The middle entries
After the exposition and the first episode the subject reappears in closely related keys: in major, the relative minor (vi), subdominant (IV), supertonic (ii), mediant (iii); in minor, the relative major (III), minor dominant (v), subdominant (iv), VI and VII. Each entry may be accompanied by the countersubject or by new counterpoints.
Map of a three-voice fugue in C major (teaching model)
| Section | Bars | Key | Content |
|---|---|---|---|
| Exposition | 1–7 | C → G → C | S, A + CS, codetta, S + CS + counterpoint |
| Episode 1 | 8–9 | C → Am | sequence on the head of the subject |
| Middle entry | 10–11 | Am | S in the bass |
| Episode 2 | 12–14 | Am → F | voice exchange of episode 1 |
| Entry | 15–16 | F | S in the soprano |
| Episode 3 | 17–19 | F → G (pedal) | sequence, preparation |
| Final entry and coda | 20–24 | C | S (possible stretto), tonic pedal |
Common mistakes
- Episodes with unrelated material: they sound like another piece. Better to derive them from the subject.
- Episodes that do not modulate: the fugue stands still.
- A countersubject too similar to the subject (same rhythm): the entries get confused.
Exercise for a producer
- Take a 2-bar riff (your "subject").
- Write a rhythmically opposite countermelody and check that it works above and below the riff.
- Create a 4-bar "episode" by repeating only the first 4 sixteenth notes of the riff in a descending sequence over Am–Dm–G–C.
- Arrange: riff + countermelody → episode with fewer instruments → riff in A minor. It is the same reasoning as a verse that evolves into a breakdown and returns.
Related topics
Fugue: subject and answer, Fugue: stretto, pedal and devices, Harmonic sequences, Invertible counterpoint, Fugue: formal plan.