Three-key exposition - AbsoluteAstronomy.com

In music, the three-key exposition is a particular kind of exposition used in sonata form

Sonata form

Sonata form is a large-scale musical structure used widely since the middle of the 18th century . While it is typically used in the first movement of multi-movement pieces, it is sometimes used in subsequent movements as well—particularly the final movement...

.

Normally, a sonata form exposition has two main key areas. The first asserts the primary key of the piece, that is, the tonic. The second section moves to a different key, establishes that key firmly, arriving ultimately at a cadence in that key. For the second key, composers normally chose the dominant

Dominant (music)

In music, the dominant is the fifth scale degree of the diatonic scale, called "dominant" because it is next in importance to the tonic,and a dominant chord is any chord built upon that pitch, using the notes of the same diatonic scale...

for major-key sonatas, and the relative major for minor-key sonatas. The three-key exposition moves not directly to the dominant or relative major, but indirectly via a third key; hence the name.

Ludwig van Beethoven

Ludwig van Beethoven

Ludwig van Beethoven was a German composer and pianist. A crucial figure in the transition between the Classical and Romantic eras in Western art music, he remains one of the most famous and influential composers of all time.Born in Bonn, then the capital of the Electorate of Cologne and part of...

wrote a number of sonata movements during the earlier part of his career with three-key expositions. For the "third" (that is, the intermediate) key, Beethoven made various choices: the dominant minor (Piano Sonata No. 2, Op. 2 no. 2

Piano Sonata No. 2 (Beethoven)

Beethoven's Piano Sonata No. 2 in A major, Op. 2, No. 2, was written in 1796 and dedicated to Joseph Haydn.-Movements:It has four movements:*I. Allegro vivace 2/4*II. Largo appassionato 3/4 D major...

; String Quartet No. 5, Op. 18 no. 5

String Quartet No. 5 (Beethoven)

Ludwig van Beethoven's String Quartet No. 5 in A major was published in 1801 as opus 18, no. 5, and was written between 1798 and 1800. Beethoven modeled this quartet directly on Mozart's quartet in the same key .-Movements:...

), the supertonic

Supertonic

In music or music theory, the supertonic is the second degree or note of a diatonic scale, one step above the tonic. In music theory, the supertonic chord is symbolized by the Roman numeral ii in a major scale, indicating that the chord is a minor chord , or ii in a natural minor scale, indicating...

minor (Piano Sonata No. 3, Op. 2 no. 3

Piano Sonata No. 3 (Beethoven)

Ludwig van Beethoven's Piano Sonata No. 3 in C major, Op. 2, No. 3, is a sonata written for solo piano, composed in 1796. It is dedicated to Franz Joseph Haydn...

), and the relative minor (Piano Sonata No. 7, Op. 10 no. 3

Piano Sonata No. 7 (Beethoven)

Ludwig van Beethoven's Piano Sonata No. 7 in D major, Op. 10, No. 3, was dedicated to the Countess Anne Margarete von Browne, and written in 1798. This makes it contemporary with his three string trios opus 9, the violin sonatas of opus 12 and the violin romance that became his opus 50 when later...

). Later, Beethoven used the supertonic major (Piano Sonata No. 9, Op. 14 no. 1

Piano Sonata No. 9 (Beethoven)

The Piano Sonata No. 9 in E major, Op. 14, No. 1, is an early-period work by Ludwig van Beethoven, dedicated to Baroness Josefa von Braun. It was composed in 1798 and transcribed - not arranged - for string quartet by the composer in 1801 , the result containing more quartet-like passagework and...

, Piano Sonata No. 11, Op. 22

Piano Sonata No. 11 (Beethoven)

Beethoven's Piano Sonata No. 11 in B-flat major, Op. 22, composed in 1800.Prominent musicologist Donald Francis Tovey has called this work the crowning achievement and culmination of Beethoven's early "grand" piano sonatas....

), which is only a mild sort of three-key exposition, since the supertonic major is the dominant of the dominant, and commonly arises in any event as part of the modulation.

As he entered his so-called "middle period," Beethoven abandoned the three-key exposition. This was part of a general change in the composer's work in which he moved closer to the older practice of Haydn

Joseph Haydn

Franz Joseph Haydn , known as Joseph Haydn , was an Austrian composer, one of the most prolific and prominent composers of the Classical period. He is often called the "Father of the Symphony" and "Father of the String Quartet" because of his important contributions to these forms...

, writing less discursive and more closely organized sonata movements.

Franz Schubert

Franz Schubert

Franz Peter Schubert was an Austrian composer.Although he died at an early age, Schubert was tremendously prolific. He wrote some 600 Lieder, nine symphonies , liturgical music, operas, some incidental music, and a large body of chamber and solo piano music...

, who liked discursive forms for the entirety of his short career, also employed the three-key expositions in many of his sonata movements. A famous example is the first movement of the Death and the Maiden Quartet in D minor, in which the exposition moves to F major and then A minor (translated to D major and minor respectively in the recapitulation). The first movement of the second cello sonata by Brahms

Johannes Brahms

Johannes Brahms was a German composer and pianist, and one of the leading musicians of the Romantic period. Born in Hamburg, Brahms spent much of his professional life in Vienna, Austria, where he was a leader of the musical scene...

also employs a three-key exposition moving to C major and then A minor. The first movement of Frederic Chopin

Frédéric Chopin

Frédéric François Chopin was a Polish composer and virtuoso pianist. He is considered one of the great masters of Romantic music and has been called "the poet of the piano"....

's Piano Concerto in F Minor

Piano Concerto No. 2 (Chopin)

The Piano Concerto No. 2 in F minor, Op. 21, is a piano concerto composed by Frédéric Chopin in 1830. Chopin wrote the piece before he had finished his formal education, at around 20 years of age. It was first performed on 17 March 1830, in Warsaw, Poland, with the composer as soloist. It was...

also has a three-key exposition (F minor, A-flat major, C minor).

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