Chromatic Fantasia and Fugue, BWV 903

The Chromatic Fantasia and Fugue in D minor, BWV 903, is a work for harpsichord by Johann Sebastian Bach. Bach probably composed it during his time in Köthen from 1717 to 1723. The piece was already regarded as a unique masterpiece during his lifetime. It is now often played on piano.

Structure
Because of its frequent use of semitones, this piece became known as Chromatic.

Fantasia
The chromatic fantasia begins as a toccata with fast, up and down surging runs in thirty-second notes (demisemiquavers) and broken chords in sixteenth-note (semiquaver) triplets, which are often diminished seventh chords lined up in semitones. The second part is a series of very clear and remotely modulating soft leading chords that are written in the oldest copies as "Arpeggio", i.e. they require a spread chord. The third part is entitled Recitative and includes a variety of ornamented, enriched, highly expressive melodies. This part contains several enharmonic equivalents. The recitative finishes with passages that are chromatically sinking diminished seventh chords over above the pedal point on D.

Fugue
The theme of the fugue begins with an upward chromatic line from the fifth of D minor to the seventh, moving from A to C. The following phrase emphasizes D minor.

Then the tonal answer, the second voice, appropriately begins on D, moving through a sequence that takes D minor and changes it to D major, leading us towards G minor then back through A major (dominant) to D minor. To sum up, first voice harmonies can be hear as D minor, A minor, D major, G minor, then back to tonic via A major, D minor. The harmonies of the second voice (tonal answer) may be heard as D minor G minor G major A major D minor.

Reception and interpretation
The virtuosic and improvisational toccata style of the fantasy, in which both hands alternate rapidly, the expressive, tonally experimental character and the key of D minor put the work alongside the famous Toccata and Fugue in D minor, BWV 565. Both works are exceptional and therefore particularly popular compositions in Bach's keyboard music. This assessment was shared by Bach's contemporaries. The first biographer of Bach, Johann Nikolaus Forkel, wrote: "I have expended much effort to find another piece of this type by Bach. But it was in vain. This fantasy is unique and has always been second to none."

19th-century interpretations of the piece are exemplars of the romantic approach to Bach's works taken during that period. Felix Mendelssohn, the founder of the Bach revival, played this fantasy in February 1840 and 1841 in a series of concerts at the Leipzig Gewandhaus and delighted the audience. He attributed this effect to the free interpretation of the fantasy's arpeggios. He used the sound effects of the era's grand piano through differentiated dynamics, accentuating high notes and doubling pedal bass notes. This interpretation became the model for the adagio of Mendelssohn's second sonata for cello and Piano (Op. 58), written from 1841 to 1843. This work gives the top notes of the piano arpeggios a chorale melody while the cello plays an extended recitative resembling that of the Chromatic Fantasia and quotes its final passage.

This romantic interpretation was formative; many famous pianists and composers, including Franz Liszt and Johannes Brahms, used the work as a demonstration of virtuosity and expressiveness in their concert repertoire. It was reprinted in many editions with interpretive notes and scale instructions. Max Reger reworked the piece for the organ. Even since the rise of the historically informed performance movement, it remains one of the most popular keyboard works by Bach.

There are romantic interpretations by Edwin Fischer, Wilhelm Kempff, Samuil Feinberg and Alfred Brendel on the grand piano, and by Wanda Landowska on the harpsichord. A non-romantic interpretation with surprising accents and without pedalling was presented by Glenn Gould and influenced more recent pianists such as András Schiff and Alexis Weissenberg. The pianist Agi Jambor combined romantic sonorities and colors with clear voice guidance and emphasized the work's structural relations. Around 1944, Kaikhosru Shapurji Sorabji composed a virtuosic paraphrase of the fantasy as the 99th of his 100 Transcendental Studies.

Transcriptions
The work has been transcribed for solo viola by Zoltán Kodály in 1950. There is a transcription for classical guitar by Philip Hii, and Busoni made two transcriptions for both solo piano and cello and piano, which are catalogued as BV B 31 and 38, respectively. Jaco Pastorius played the opening parts on electric bass on his 1981 album Word of Mouth. A transcription for solo cello was made by cellist Johann Sebastian Paetsch in 2015 and published by the Hofmeister Musikverlag in Leipzig. A transcription for solo clarinet of the fantasy was done by Stanley Hasty, professor emeritus of University of Rochester's Eastman School of Music, in 2002. A transcription of the Chromatic Fantasia for solo B♭ clarinet, and fugue in D minor for 3 clarinets (two B♭ clarinets and B♭ bass clarinet) was made by clarinetist Richard Stoltzman in 2011 and published by Lauren Keiser Music.

Literature
Urtext edition
 * Rudolf Steglich (ed.): Johann Sebastian Bach: Chromatische Fantasie und Fuge d-moll BWV 903: Urtext without fingerings. G. Henle, 2009,
 * Heinrich Schenker: J.S. Bach's Chromatic Fantasy and Fugue: Critical Edition With Commentary. Longman Music Series, Schirmer Books 1984, ISBN 0028732405

Musical analysis
 * Martin Geck (ed.): Bach-Interpretationen. Vandenhoeck und Ruprecht, 2nd edition, Göttingen 1982, ISBN 3525332769, p. 57–73 and 213–215
 * Ulrich Leisinger, Michael Behringer (eds.): Johann Sebastian Bach: Chromatische Fantasie + Fuge (BWV 903/903a). Klavier, Cembalo. Wiener Urtext Edition, Schott Verlag, ISBN 978-3-85055-597-5
 * Stefan Drees: Vom Sprechen der Instrumente: Zur Geschichte des instrumentalen Rezitativs. Peter Lang, Frankfurt am Main 2007, ISBN 3631564783, p. 75–78