Writing a Fugue from scratch (?)

After writing a few fugues from partimento – we can work towards writing a fugue from scratch (or at least without a given partimento)

So where do we start?

Before we jump into writing fugues from scratch we review the Alto Clausula Variant 5-4-3 – which is the basis of evaded cadences from the dominant back down to a 6/3 chord on Mi.

Our original Alto Clausula was 5-5-5, as can be seen in the standard double cadence

The 5-4-3 variant allows us to evade the cadence by putting it in the lowest voice of the texture

Evaded cadence – Blue is Alto Clausula, Red is Soprano Clausula (twice), Green is a Tenor Clausula

This type of evaded cadence is extremely important when we want to write fugues (and other original works).

  • It allows us to cadence without full closure
  • All the intervals in the evaded cadence can be inverted, so three clausulae create an opportunity for six invertible counterpoint variants
Invertible counterpoint possibilities of the evaded cadence in three parts

If we added diminutions to each of these clausulae, we could think of each of these as a subject, a countersubject, and a second countersubject. This type of thinking will help us create a fugue.

Step 1

Most fugue subjects begin on 5 or 1 and end on 3 (the stable tones of the scale) – and most outline the Alto Clausula Variant at their ending

Bach fugue BWV 571 subject as diminution of 5-4-3

Since this subject is merely a diminution of the Alto Clausula Variant, the counterpoint to it can be a Soprano Clausula, a Tenor Clausula, the regular Alto Clausula, and even the Bass Clausula (in the bass)

The same subject with a soprano and tenor clausula above it

Very often 5-4-3 is ornamented as 5-6-5-4-3

Bach fugue BWV 856 subject elaborating 5-6-5-4-3
Bach fugue BWV 870 subject elaborating 5-6-5-4-3
Bach fugue BWV 857 subject elaborating 5-6-5-4-3

In the article Structural Patterns in Fugue Subjects and Fugal Expositions, William Renwick identifies four variants of this basic paradigm and their respective answer paradigms:

Variants of 5-4-3 underlying voice leading in fugue subjects by Bach. (T) stands for tonal answers and (R) for real answers

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