A fugue (French) or fuga (Italian) is a polyphonic composition with two or more voices, built on a subject (theme) introduced at the beginning. Each successive voice enters in imitation of the subject in a manner similar to singing Row, row, row your boat. As such, the fugue is a wholly polyphonic composition, harkening back to the textures and techniques of the Renaissance. Polyphonic writing during the Baroque was a technically demanding style and mainly popular in Northern Europe, culminating with the music of Johann Sebastian Bach.
Baroque Organ Pipes | Chiesa di San Agnese in Agone, Rome, Italy | The coffin beneath the organ is likely the tome of an important musician or music patron.
Fugues use techniques beyond the simple imitation or echoing of Row, row, row your boat. For example, after the initial sounding of a subject, subsequent statements of the subject are heard with distinctive counterpoint known as a countersubject.
Composers dramatize and develop the fugue subject by using a variety of techniques such as pedal point, inversion, retrograde, augmentation, diminution and stretto.
A pedal point is a sustained tone, typically in the bass, that continues sounding as the harmony changes, alternating between consonance and dissonance as the chords progress.
Inversion refers to flipping the contour of a melodic figure. In other words, an inversion of a melodic figure has the same rhythm as the original figure, but the contour moves in the opposite direction. The top staff is an inversion of the the bottom staff.
A melodic figure which is the reverse of a previously or simultaneously stated figure is said to be in retrograde. In other words, it is played backwards.
Augmentation is a lengthening of duration values while retaining the same pitches. For example, the augmentation of the notes below are twice as long:
Diminution refers to a shortening of duration values while retaining the same pitches. For example, the diminution of the notes below are half as long:
The technique of stretto refers to the subject being imitated before it’s fully stated. This is basically the technique used when you sing Row, row, row your boat: phrases overlap and pile up one over another.
The technique and art of writing a fugue, using the above techniques and many others, is called counterpoint.
Bach's "Little" Fugue in G Minor
Fugue in G minor, BWV 578, (Little Fugue in G Minor), is an organ fugue composed by Johann Sebastian Bach while employed at Arnstadt (1703–1707). Like most fugues, it is organized into three sections: exposition, development, and return of the subject in the fugue's tonic (original) key.
Bach's "Little" Fugue in G Minor BWV 578 | Autograph Score | Leipzig Bach Archive
A fugue begins with the exposition of the subject in the tonic key. After the statement of the subject, a second voice, known as the answer, enters and states the subject with the subject transposed to a closely related key. Once all the voice entries have appeared, they interweave a bit and cadence, forming the exposition of the fugue.
The opening subject of Little Fugue in G Minor is one of Bach's most recognizable melodies:
Bach's Little Fugue in G Minor has four voices, so you'll hear each of the four voices present the subject in the exposition. Subject statements are back to back, starting from the highest voice and progressing to lower voices, one after another, until the final voice is sounded in the pedals. The entrance of the second voice, after the initial statement of the subject, is accompanied by a countersubject moving in faster notes. Performance of this piece requires two hands and two feet!
In the development, the Bach continues to work the material introduced in the exposition, but dramatizes it with modulation and free form manipulation of the subject (see techniques detailed above). The sections featuring free treatment of material is called episodes. The episode is usually followed by a statement of the subject to help anchor the listener and provide a sense of formal organization.
Finally, a sense of return is created by bringing back the original key and stating the subject in its entirety, often cascading subject entries for increased excitement. Finally, Little Fugue in G Minor ends with a big cadence on a G major chord. The practice of ending a minor mode piece with a major chord is called a Picardy third. It was thought the major chord provided a stronger and happier ending than a minor chord.
"Little" Fugue in G minor BWV 578 | Johann Sebastian Bach (1685–1750)
Organ Pipes | Maria della Vittoria, Rome, Italy | The organ was an important instrument for churches and they often spared no expenses for these installations.
fugue, fuga, exposition, answer, episode, countersubject, pedal point, inversion, retrograde, augmentation, diminution, stretto, counterpoint, Picardy third