Questions: Canon and Fugue Composition Basics

Question 1

In a two-voice canon, why must the composer think about counterpoint when writing the dux (leader) alone?

Model answer: Because the comes (follower) will reproduce the dux exactly, offset in time. Every measure of the dux will sound simultaneously with an earlier measure of the same melody. So when writing bar 3 of the dux, the composer must ensure it forms good counterpoint with bar 1 — the two bars will be heard together. The single line is always in counterpoint with itself.

This is the defining constraint of canon writing. Unlike free counterpoint, where two independent lines are composed against each other, a canon forces the composer to write one line that works as both melody and counterpoint simultaneously. The time interval and pitch interval of the imitation determine which measures will be in contact, so the composer must plan ahead for every upcoming vertical collision.

Question 2

What is the difference between a fugue exposition and a fugue episode?

• A. An exposition uses the full subject; an episode develops fragments without a complete subject statement
• B. An exposition is in the tonic; an episode is always in a minor key
• C. An exposition uses all voices; an episode uses only two voices
• D. An exposition is the second section of a fugue; an episode is the opening

Answer: (A)

The exposition is the opening section where the subject enters successively in each voice. Episodes are transitional passages between full subject entries; they develop motivic fragments (often from the subject's tail or from a countersubject) using sequential motion, but they do not present the complete subject. Episodes are the fugue's connective tissue, driving harmonic motion between the key areas where full subject entries occur.