Köchel catalogue

• 1. Introduction

  ›

  The Köchel catalogue assigns a single number to every piece Wolfgang Amadeus Mozart ever wrote. When you hear someone refer to "K. 626," they mean the Requiem in D minor, the 626th composition Köchel counted. That shorthand, two letters and a number, now appears on concert programmes, record sleeves, and music library shelves the world over. But behind it lies a stranger story than the tidy reference system suggests: a 551-page private project completed in 1862 by a man who was not a professional musicologist, a catalogue that was out of date almost before the ink dried, and a numbering scheme that has been revised, argued over, and overhauled for more than 160 years. How do you put a composer in order when the composer himself was only intermittently systematic? And what happens when scholars keep finding more music than anyone expected? Those are the questions the Köchel catalogue has been trying to answer ever since Ludwig von Köchel sat down to count.

• 2. Köchel's Original Project

  ›

  Ludwig Ritter von Köchel published his catalogue in 1862, more than seventy years after Mozart's death in 1791. The decades between had not been idle: Franz Gleißner and Johann Anton André had both attempted catalogues, with André's version appearing in 1833. None produced anything comprehensive enough to settle the question of what Mozart had actually written and in what order. Köchel's 551-page volume, titled Chronological-thematic Catalogue of the Complete Musical Works of W. A. Mozart, was the first to attempt a complete accounting. Each entry included the opening bars of the piece, called an incipit, giving readers a musical fingerprint alongside the catalogue number. Köchel divided the entire body of work into a main chronology of 626 compositions and five appendices, the Anhänge, covering lost authentic works, fragments, transcriptions by others, doubtful works, and misattributed works. The task of dating was genuinely difficult. Many pieces written before 1784 could only be estimated. Köchel leaned on a partial list that Leopold Mozart had compiled of his son's earlier output. Beginning in February 1784 with the Piano Concerto now known as K. 449, Mozart himself kept a thematic catalogue of his own compositions, which allowed later scholars to date his works from that point with much greater precision. Before 1784, Köchel was largely working from manuscript evidence and inference.

• 3. The Renumbering Problem

  ›

  A strictly sequential numbering system has no room to grow. Once Köchel had counted to 626, any work discovered later, redated, or rescued from the doubtful appendix had nowhere to go in the main list. The second edition in 1905 addressed this only modestly, adding pieces that had since come to light. It was the third edition in 1937, edited by Alfred Einstein, that changed the system's logic. Einstein followed the analyses of Théodore de Wyzewa and Georges de St. Foix, reassigning works from the original appendices into the main catalogue by inserting numbers with lower-case letter suffixes. A piece could become K. 196e, slotted between K. 196 and K. 197, displacing nothing but muddying the sequence. The Divertimento for Wind Octet in E illustrates the resulting chaos. Köchel had placed it at K. Anh. 226 in the doubtful appendix. Einstein promoted it to K. 196e. The sixth edition in 1964 demoted it again to K. Anh. C 17.01. A later edition restored Einstein's K. 196e, though the work is still considered doubtful. That single piece carries four different catalogue identities across the editions. By the time the ninth edition appeared in 2024, edited by Neal Zaslaw, the confusion of renumbering between versions had grown serious enough that Zaslaw abandoned chronological ordering entirely. All works already in the catalogue returned to the oldest number they had ever been assigned. Works newly included in the ninth edition received numbers starting past 626, running all the way to 721.

• 4. What the List Contains

  ›

  The composition list that runs through the catalogue begins with a cluster of small piano pieces Mozart wrote at age five in Salzburg in 1761, including an Andante in C and a Minuet in F dated the 16th of December 1761. The final numbered work in Köchel's original count, K. 626, is the Requiem. Between those two endpoints sit symphonies, string quartets, violin sonatas, operas, masses, divertimenti, concertos, dances, canons, songs, and fragments in quantities that stagger the imagination. The catalogue also tracks works that exist in unusual forms: 64 cadenzas Mozart wrote to his own keyboard concertos are grouped under K. 626a I, while K. 626a II covers cadenzas he wrote to concertos by other composers. K. 626b collects 42 sketches and other fragments. The appendices acknowledge works by Leopold Mozart mistakenly attributed to his son, pieces identified since 1965 as actually by Michael Haydn, and compositions in Appendix C that have since been more reliably assigned either to other composers or to Mozart himself. The sixth edition restructured these appendices considerably, grouping doubtful and misattributed vocal works in C 1-10 and instrumental works in C 11-30.

• 5. Complete Recordings

  ›

  Philips Classics Records marked the bicentenary of Mozart's death in 1991 by releasing a 180-CD collection in 45 box sets, each disc in a jewel case, under the title The Complete Mozart Edition. The recordings were assembled from world-renowned artists and were produced between 1990 and 1991. A selection of 25 discs from that set, called The Best of the Complete Mozart Edition, appeared in 1995. The full collection was then reissued as 17 box sets under the title The Compact Complete Mozart Edition in 2000. For Mozart's 250th birthday in 2006, Brilliant Classics released its own single box of 170 CDs, with an additional disc of liner notes and vocal libretti, titled Mozart Complete Edition. A decade later, for the 225th anniversary of Mozart's death in 2016, Decca Classics and Deutsche Grammophon partnered with the International Mozarteum Foundation to release Mozart 225: The New Complete Edition, a box of 200 CDs with two hardback books. One of those books offered a new Mozart biography by Cliff Eisen; the other contained a newly developed short Köchel guide. The 2016 set includes premiere performances of previously lost compositions, never-recorded fragments, key works in alternative versions, and recordings of legendary historic performances.