What is a Fugue?

By Edwin Hall Pierce

A fugue is a piece of music formed by the recurrence of the same theme in several different voices, according to certain strict laws of imitation. These laws have not been invented by composers or theorists any more than the laws of waveforms have been invented by mathematicians. They have simply been discovered. Theorists record them, not to place a limit on the possibility of music creation, but as a guide and help to young composers. In listening to a fugue, it is not at all necessary to pleasure that one should understand these laws. One is simply conscious of the surging motion of music and underlying unity.

The reason many people do not enjoy fugues, is that they are accustomed to listen for a single predominant melody as in a song for a solo voice, the harmony being to them only for enrichment, like the gravy on meat. Not that a fugue has no melody – the trouble is, in fact, that it is all melody – soprano, alto, tenor and bass alike – and the inexperienced ear cannot take in so much at once.

When a pianist hears the word “fugue” he instinctively recalls Bach’s Well-Tempered Clavier; but the first fugues were vocal, not instrumental. Even in speaking of instrumental fugues we still use the term “voices” to describe the different parts which enter one by one at different pitch. In Handel’s Messiah, Haydn’s Creation and other of the older oratorios, nearly all the choruses are vocal fugues with orchestral accompaniment. As we approach our own day, fugue writing becomes less frequent. Mendelssohn and Gounod, for instance, use it only occasionally. Much of the ancient church music, for instance the Masses of Palestrina or of Byrd, is in the form of unaccompanied vocal fugues. The organ is a particularly grateful medium for the presentation of fugues.

We now come to the technical structure of the fugue.

The “Subject”

Fugues are written for a certain definite number of “voices,” from two to give, but the favorite number is four – soprano, alto, tenor and bass. Any voice may begin, according to the composer’s fancy, and the first thing it sings is the subject. For a vocal fugue, the first requirement is that it be singable in character and not too great in compass. This, to begin with; but there are several other considerations which an experienced composer learns to take into account. For instance, its fitness for an “answer” and its opportunities for a possible “stretto” – two things which we will explain later.


(This last example illustrates the somewhat rare case of a double subject, starting what is called a Double Fugue.)

In an instrumental fugue, as it is more difficult to preserve the individuality of the voices, the composer takes great pains usually to device a subject which has a strongly marked character, so that it may be easily recognized no matter how concealed among the “voices.” This “character” may consist in unusual melodic intervals, peculiar rhythm, or anything else which serves the desired purpose. We give a few examples:


This exhibits a striking character in the intervals of the melody.


This exhibits rhythm easily attracting the attention.


This has a peculiar opening and shutting effect, reminding one of a pair of scissors.

Generally a fugue subject is quite brief. If it is longer, it is usually in rapid time and contains “sequences” (repetitions of the same motive a degree higher or lower.)


It is very seldom that a theme drawn from a song, dance, modern hymn tune or other music of a modern type would be suitable for a fugue subject; because such a theme contains within itself the laws of periodic construction. It has a regular recurrence of cadences, whereas the very essence of a good fugue is its great flow and its almost entire avoidance of cadences and marked divisions of any kind. To realize this you only have to try to take half a fugue for a lesson, and see if you can find any good place at which to stop.

The “Answer”

At the close of the “subject” (sometimes slightly before the close) a second voice starts in with the “answer.” The answer is essentially nothing but the subject transposed into the key a fifth higher, or, which is the same thing, a fourth lower. But there are certain licenses allowed and indeed required, in order to keep the answer from leading on to a more distant and undesired key, as the entry of the third voice, which has presently to take place, must be in the original key.

The exact determination of these licenses is of a highly technical nature and to enter fully into a discussion of them would lead us too far afield. Suffice it to say that the tonic (first note of the scale), and, conversely, the dominant by the tonic, notwithstanding the fact that in the first case the interval is a fifth and in the other case only a fourth. One may compare it to “foreshortening” in drawing. A round wheel, seen from the front, is a circle; seen from a little at one side it is an ellipse. Occasionally one finds a subject which can be answered without the least change. The fugue is then called a “real fugue;” but the term is unfortunately chosen, as the greater number of good fugues are of the other kind, called “tonal fugues,” and are just as genuine fugues.


Of these to examples, the first shows a “tonal” answer, the second a “real” answer, so-called.

Besides the change of interval that takes place in the tonal fugues, there is another license occasionally found in “answers”: the first note may be shortened.


Why Imitate at the Fifth?

Sometimes pupils of an inquiring mind ask the question, “Why pick on the fifth as an interval of imitation?” “Why not use some other interval for variety?” As a good illustration that Fugue rests on natural laws, and not on the arbitrary say-so of theorists, it seems interesting to answer this question. Imitation of one voice by another is possible at any interval, and examples may be found at the Unison, Second, Third, Fourth, Fifth, Sixth, Seventh or Octaves.

Of these, we may dismiss the Unison as being lacking in variety. The Octave is in fact in use, but is more convenient for the third voice than the second. The fourth actually is more or less in use in certain parts of “tonal” answers. That reduces us to the second, third, sixth and seventh. We give a subject and a choice of two different answers: The first keeps the proper relative intervals, but takes us into so remote a key that it will be very clumsy trying to get back again for the entry of the next voice. The second keeps in the same key; but the character of the theme is lost by the change in position of the semitones.


A similar problem would be met with, even if less extreme, in case of the Second, Third and Sixth.

Another good reason for the choice of the intervals of imitation is common use is the fact that in vocal fugue they are peculiarly convenient for the requirements of the human voice. The compass of basses and tenors differs by about the interval of a fifth, and so does the compass of sopranos and altos. The compass of basses and altos differs by about an octave, and so does the compass of tenors and sopranos. Hence nothing could be more convenient.

The “Counter-subject”

When the second voice begins the answer, the first voice continues as a sort of accompaniment to it. If what it sings is a real new theme and is used again repeatedly by other voices for a similar purpose, it is called a Counter-subject, but if it is of no great significance and is changed freely later on, or other material substituted, it is better to call it simply “counter point to the subject.” In the former case, the fugue is called “strict;” in the latter, “free.”

The “Exposition” and What Follows

When all the voices have had their chance at the subject or answer, the “Exposition” is said to be complete. There follows a shorter or longer bit of free writing, and then the subject and answer begin to appear again, one at a time, in the various voices. The structure of this part of the fugue is very free. There is usually more modulation, and the entries may be in any order; only in good fugues, whenever a voice has a rest, it usually enters again with the subject or answer. Bits of free writing intervene here and there, called “Episodes.” In short fugues, these are scarcely distinguishable in style from the rest of the fugue, except for the fact that they are neither the subject or the answer. In long instrumental fugues, for instance Bach’s E minor organ Fugue (Peters book II), the episodes are brilliant little bits of free writing not in any way related to the subject, but giving an entire contrast.

The “Stretto”

Toward the latter part of most fugues it is the custom to have the answer follow the subject at a shorter interval of time; overlapping it. Sometimes there are several successive strettos, in which case, the closer ones come last. Some subjects afford no chance of a stretto. If a composer wishes one, he generally plans for it when he is inventing the subject. Sometimes he even writes the stretto first.


The Pedal

Near the end of a fugue there is often a low note in the bass, held for several measures, on the dominant. This is called a Dominant Pedal. At the very end there may be a similar long held note on the tonic. These may come after the stretto, but more often it is combined with one or both of them. Neither a stretto nor a pedal is absolutely necessary to a fugue, but they add greatly to its effectiveness if well placed, forming a climax.

Another device to form a climax to a fugue, and often used by Handel – never so far as we know, by Bach – is to suddenly cease from contrapuntal writing and present the subject simply harmonized with dignified and majestic chords.

Unusual Examples in the Art of Fugue

Sometimes exceptional forms of imitation are found, either in the Exposition or Stretto; for instance, imitation is contrary motion.


In Bach’s Organ Fugue in C major (Peters Book II), the subject is


and the pedal keyboard of the organ is not used until near the end of the fugue, when the subject is heard in the deep pedal notes for the first time, but played twice as slow


while the hands keep up the usual lively movement. This is called “augmentation,” and must not be confused with what we have described as the “Pedal” of a fugue, which is a long sustained note in the bass.

Examples are said to exist of “diminution” – the “answer” coming on the scene at double speed, but I do not recall any instance worth quoting.

Bach was the greatest of fugue writers; since his day there has been a reaction and the art is less and less cultivated, yet it has never been allowed to die.