In music, an invention is a short composition (usually for a keyboard instrument) in two-part

counterpoint In music, counterpoint is the relationship between two or more musical lines (or voices) which are harmonically interdependent yet independent in rhythm and melodic contour. It has been most commonly identified in the European classical tradi ...

. (Compositions in the same style as an invention but using three-part counterpoint are known as '' sinfonias.'' Some modern publishers call them "three-part inventions" to avoid confusion with

symphonies A symphony is an extended musical composition in Western classical music, most often for orchestra. Although the term has had many meanings from its origins in the ancient Greek era, by the late 18th century the word had taken on the meaning com ...

.) Well-known examples are the fifteen inventions that make up the first half of Johann Sebastian Bach's Inventions and Sinfonias. Inventions are usually not performed in public, but serve as exercises for keyboard students, and as pedagogical exercises for composition students.

Form

Inventions are similar in style to a

fugue In music, a fugue () is a contrapuntal compositional technique in two or more voices, built on a subject (a musical theme) that is introduced at the beginning in imitation (repetition at different pitches) and which recurs frequently in the c ...

, though they are much simpler. They consist of a short exposition, a longer development, and, sometimes, a short recapitulation. The key difference is that inventions do not generally contain an answer to the subject in the dominant key, whereas the fugue does. Two-part and three-part inventions are in contrapuntal style.

Exposition

In the exposition, a short

motif Motif may refer to: General concepts * Motif (chess composition), an element of a move in the consideration of its purpose * Motif (folkloristics), a recurring element that creates recognizable patterns in folklore and folk-art traditions * Moti ...

is introduced by one voice in the

tonic key Tonic may refer to: *Tonic water, a drink traditionally containing quinine *Soft drink, a carbonated beverage *Tonic (physiology), the response of a muscle fiber or nerve ending typified by slow, continuous action * Tonic syllable, the stressed syl ...

. This is also known as the theme. The subject is then repeated in the second voice in the

while the initial voice either plays a

countersubject In music, a subject is the material, usually a recognizable melody, upon which part or all of a composition is based. In forms other than the fugue, this may be known as the theme. Characteristics A subject may be perceivable as a complete mus ...

or plays in

free counterpoint In music, counterpoint is the relationship between two or more musical lines (or voices) which are harmonically interdependent yet independent in rhythm and melodic contour. It has been most commonly identified in the European classical tra ...

Development

The development comprises the bulk of the piece. Here the composer develops the subject by writing

variations Variation or Variations may refer to: Science and mathematics * Variation (astronomy), any perturbation of the mean motion or orbit of a planet or satellite, particularly of the moon * Genetic variation, the difference in DNA among individuals ...

either

melodically A melody (from Greek μελῳδία, ''melōidía'', "singing, chanting"), also tune, voice or line, is a linear succession of musical tones that the listener perceives as a single entity. In its most literal sense, a melody is a combinat ...

or harmonically. This usually involves the alternation of episodes with statements of the theme, similar to the development of a fugue. In minor- and major-mode inventions, the theme is typically restated in the relative major and the dominant, respectively. New key areas are reached through episodes, which usually move sequentially through the circle of fifths. The final episode ends on a half cadence in the original key, and is often exaggerated to make the subject sound extra special when it returns. David Fuentes, "Figuring out Melody" Many of Bach‘s Inventions follow this plan, including BWV 775 and

BWV 782 The Inventions and Sinfonias, BWV 772–801, also known as the Two- and Three-Part Inventions, are a collection of thirty short keyboard compositions by Johann Sebastian Bach (1685–1750): 15 ''inventions'', which are two-part contrapuntal piece ...

Recapitulation

If an invention does have any recapitulation at all, it tends to be extremely short—sometimes only two or four measures. The composer repeats the theme in the upper voice and the piece ends. The repetition of the theme contains very little variation (or no variation at all) on the original theme. The lower line usually plays the countersubject, and if there is no countersubject, plays in free counterpoint.

History

The invention is primarily a work of Johann Sebastian Bach. Inventions originated from contrapuntal

improvisation Improvisation is the activity of making or doing something not planned beforehand, using whatever can be found. Improvisation in the performing arts is a very spontaneous performance without specific or scripted preparation. The skills of impr ...

s in Italy, especially from the form of the composer

Francesco Antonio Bonporti Francesco Antonio Bonporti (11 June 1672 – 19 December 1749) was an Italian priest and amateur composer. Born in Trento, he was admitted in 1691 to the ''Collegium Germanicum'' in Rome, where he studied theology. While in Rome, he also studied ...

. Bach adapted and modified the form to what is considered to be a formal invention. Bach wrote 15 inventions (BWV 772–786) as exercises for his son, Wilhelm Friedemann Bach. Bach later wrote a set of 15 three-part inventions, called sinfonias (BWV 787–801).

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