The Prelude and Fugue in B-flat major,

BWV The (, ; BWV) is a Catalogues of classical compositions, catalogue of compositions by Johann Sebastian Bach. It was first published in 1950, edited by Wolfgang Schmieder. The catalogue's second edition appeared in 1990 and the third edition in ...

866, is a keyboard composition by

Johann Sebastian Bach Johann Sebastian Bach (German: Help:IPA/Standard German, �joːhan zeˈbasti̯an baχ ( – 28 July 1750) was a German composer and musician of the late Baroque music, Baroque period. He is known for his prolific output across a variety ...

. It is the 21st prelude and fugue in the first book of ''

The Well-Tempered Clavier ''The Well-Tempered Clavier'', BWV 846–893, consists of two sets of preludes and fugues in all 24 major and minor keys for keyboard by Johann Sebastian Bach. In the composer's time ''clavier'' referred to a variety of keyboard instruments, ...

'', a series of 48 preludes and fugues by the composer. It was composed no later than 1722.

Prelude

The prelude is in common time (

4/4 time A time signature (also known as meter signature, metre signature, and measure signature) is an indication in musical notation, music notation that specifies how many note values of a particular type fit into each measure (bar (music), bar). The ...

) and is composed of 20 bars, which are split into 2 periods of 10 bars each. The first period has a

toccata Toccata (from Italian ''toccare'', literally, "to touch", with "toccata" being the action of touching) is a virtuoso piece of music typically for a keyboard or plucked string instrument featuring fast-moving, lightly fingered or otherwise virt ...

-style melody which uses demisemiquaver (32nd note) broken chords and scale passages. In the first two bars, it uses a four-note sequence which drops by a third every half-bar. This period ends with a

perfect cadence In Western musical theory, a cadence () is the end of a phrase in which the melody or harmony creates a sense of full or partial resolution, especially in music of the 16th century onwards.Don Michael Randel (1999). ''The Harvard Concise Dicti ...

in dominant key of F major. The second period uses a

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style and alternates between chords and scale progressions. The coda in bar 20 uses an extended arpeggio in the tonic that confirms the key of B-flat major. One copy of the prelude by a Bach pupil has the word ''adagio'' to the big chords in bar 11, which suggests that the second period should have a more improvisatory rhythm. Below are the opening bars of the prelude: \language "english" The

Czerny Czerny is a surname meaning "black" in some Slavic languages. It is one of many variant forms, including Czarny, Černý, Czernik, Cherney, and Čierny, among others. People Notable people with this surname include: * Adalbert Czerny (1863–194 ...

edition has an extra bar added accommodating a cadence after the 20th and final bar of the prelude, described by Tovey as "perhaps the most Philistine single printed chord in the whole history of music".

Fugue

The structure of the fugue is similar to that of

sonata form The sonata form (also sonata-allegro form or first movement form) is a musical form, musical structure generally consisting of three main sections: an exposition, a development, and a recapitulation. It has been used widely since the middle of t ...

: it has an exposition (bars 1–13), a development (bars 13–41) and a recapitulation (bars 41–48). In the exposition, the

subject Subject ( "lying beneath") may refer to: Philosophy *''Hypokeimenon'', or ''subiectum'', in metaphysics, the "internal", non-objective being of a thing **Subject (philosophy), a being that has subjective experiences, subjective consciousness, or ...

is stated in the tonic, B-flat major. The second voice enters in the dominant, F major, in bar 5, then the third voice enters in the tonic once again in bar 9. In the development, the subject is restated, then the first

episode An episode is a narrative unit within a larger dramatic work or documentary production, such as a serial (radio and television), series intended for radio, television or Streaming media, streaming consumption. Etymology The noun ''episode'' is ...

(bars 19–22) modulates the fugue to G minor, then the subject is restated twice in G minor, then C minor. The second episode (bars 30–35) then modulates the fugue to G minor, then C minor. The subject is then restated in E-flat major. In the recapitulation, the subject is restated once again, still in E-flat major, then a coda (bars 45–48) leads to a

perfect authentic cadence In Western musical theory, a cadence () is the end of a phrase in which the melody or harmony creates a sense of full or partial resolution, especially in music of the 16th century onwards.Don Michael Randel (1999). ''The Harvard Concise Dict ...

in the tonic. Below are the first two statements of the fugue: \language "english"

References

{{Authority control Preludes by Johann Sebastian Bach Fugues by Johann Sebastian Bach Compositions for keyboard Compositions in B-flat major The Well-Tempered Clavier