In the beginning, when we're selecting new repertoire to learn, as soon as we're ready, it's a good idea to pick out, among other things, a fun, rhythmic piece of some kind, such as a "jig" fugue.
These brisk works in compound duple (6/8) time are not only instructional and good for the hands and feet but have wide audience appeal as toe-tapping crowd-pleasers, which lends them to postludes for high feast days and encores for recitals.
And, at some stage, gradually, we should try our hand at writing one for ourselves.
A suitable subject can sometimes be arrived at by rhythmic transformation (same sequence of pitches, different note values) of the theme from some other work.
Generally, if we fashion a theme by starting with slower note values, then make the notes move a little faster at or near the tail end, this type of theme can morph into a fugue subject which lends itself to fugal procedure.
In the case of writing a "jig" fugue, we''re generally looking for a tuneful, quick-moving subject with a strong accent on the downbeat which either incorporates disjunct motion or will be complemented by it.
Having a countersubject is a good idea, if not a necessity, and the notes in the countersubject should move whenever notes in the subject are stationary to keep everything constantly moving.
Syncopations in the countersubject, when this is possible, will also lend additional interest.
Depending upon the outline of the subject we don't necessarily need to invert the subject and countersubjects in any entry [See blog, Inversions, Getting Started With Writing, Part VIII].
The order of keys in the various entries which follow the exposition should be worked out in advance and proceed through most, if not all, (5) related keys; an entry in an additional unrelated key or two might also be included.
Generally it's good to maintain 4 voice harmony throughout with a reduction to 2 or 3 voices during the episodes; we might also keep the episodes curtailed (4-10 measures each) using motives derived from fragments of the subject or countersubect(s); there is no "rule" that says that episodes must be of the same length.
For the close we might present the subject and its countersubject(s) over a tonic pedal point, perhaps working just the faster notes from the tail of the subject into the final measures.
This was the general plan used for Fugue a la gigue in D Major Op. 6 (photo), whose subject was derived by rhythmic transformation of the cantus firmus (c.f.) from Variations in C Major Op. 4.
It will help to download and print a hard copy of this D Major "jig" Fugue for 2 hands and follow this narrative on how it was put together, being particularly careful to observe what happens to the subject as it makes its various entries [See blog, Tweaking].
This piece is written in triple counterpoint in 4 voices with 2 countersubjects maintained throughout.
The subject in compound duple time (6/8) begins in the tenor in the home key on the 1st scale degree, thus is supplied with a real answer in the dominant (in the alto); the tenor meanwhile carries the 1st countersubject.
Dealing with the large upward leap of a major 6th in this subject so that it retains its identity without crossing neighboring voice lines is the chief challenge in writing a work of this kind.
Having been derived from the outline of the c.f. from Op. 4, the subject must be tweaked in each exposition and in the 4th entry of the exposition to get it to "fit" into the available vertical space, since this music is written on 2 staves only; getting this to work successfully is the chief thing to be learned from this work.
After a very short interlude or codetta of 2 bars which brings about a return to the home key the 3rd entry comes in the soprano, the alto carries the 1st countersubject, and the tenor carries a 3rd line which, since it's repeated throughout the Fugue, becomes the 2nd countersubject.
After 2 more measures the subject, with its upward leap accomodated, makes its 4th entry in the bass, the soprano carries the 1st countersubject, the alto carries the 2nd countersubject, and a free voice in the tenor rounds out the 4 voice harmony, all in expected common practice style.
A 3 voice episode of 10 bars follows which modulates to the relative key (b minor), where the subject (with leap accomodated) enters in the soprano, the 1st countersubject in the tenor, the 2nd countersubject in the bass, and a free voice is assigned to the alto.
Another 3 voice modulating episode brings the music to the subdominant relative (e minor), where the subject (again with leap accomodated) enters in the bass, the 1st countersubject in the alto, the 2nd countersubject in the tenor, and the free voice in the soprano.
Another 3 voice episode of 4 measures follows, after which the subject enters again with leap accomodted, this time in the alto, the 1st countersubject in the tenor, the 2nd countersubject in the soprano, and the free voice in the bass.
After this, another 4 voice episode modulates to the dominant key (A) where the subject enters in the bass (leap accomodated), the 1st countersubject in the soprano, the 2nd countersubject in the alto, and the free voice in the tenor.
A sequence of 4 measures follows which leads into the stretto section and a coda which brings the work to a close in 6 voices for full organ; during this stretto and coda the subject returns to its unaltered outline with its upward leap intact.
Creating something like this is an indication that a classroom fugue can be written in obedience to the general rules of part writing and the rules of common practice and still have it come out with a modicum of tunefulness and interest.
In this work we note that in 11 different measures 2 different voices meet at a "near miss" interval of a minor 2nd (or it's dissonant cousin, a minor 9th), which introduces a little "sparkle," color, and spice and generates additional interest [See blog, Getting Started With Writing, Part XXI, Do The Unexpected].
Any time we spend studying and learning how a "jig" fugue like this is put together is time well spent.
It's necessary to caution organists, as they contemplate the study needed to embark on writing their first fugue, about the kind of textbook (Cherubini's "Course of Counterpoint and Fugue" is the most notorious) which purports to lay down regulations as to the requirements of a "properly written" fugue, and which is contradicted at every turn by the real music of the fugues of masters like Handel and J.S. Bach.
Fugue writing, as the student will quickly learn, is a vast subject where the scope for variety is almost infinite; the immensity of that scope is shown in the models left to us by the masters, and Bach above all.