The Köchel catalogue () is a catalogue of compositions by Wolfgang Amadeus Mozart, originally created by Ludwig Ritter von Köchel, in which the entries are abbreviated K. or KV. Its numbers reflect the ongoing task of compiling the chronology of Mozart's works, and provide a shorthand reference to the compositions. For example, according to Köchel's counting, Requiem in D minor is the 626th piece Mozart composed, thus is designated K. 626.
Köchel's original catalogue (1862) has been revised several times. Catalogue numbers from these revised editions are indicated either by parentheses or by superscript: K. 49 (47d) or K. 47d refers to the work numbered 47d in the sixth edition. The catalog was originally chronological, though revisions made chronological ordering of Mozart's works difficult and as of 2024 a new organizational system is used for the ninth version.
History In the decades after Mozart's death in 1791 there were several attempts to catalogue his compositions, for example by Franz Gleißner and Johann Anton André (published in 1833), but it was not until 1862 that Ludwig von Köchel succeeded in producing a comprehensive listing. Köchel's 551-page catalogue was titled (Chronological-thematic Catalogue of the Complete Musical Works of W. A. Mozart). Alt URL Köchel attempted to arrange the works in chronological order, but many compositions written before 1784 could only be estimated, although Leopold Mozart had compiled a partial list of his son's earlier works; Mozart's catalogue of his own compositions (begun in February 1784 with K. 449) allows relatively precise dating of many of his later works. The catalogue included the opening bars of each piece, known as an incipit. Köchel divided the corpus into a main chronology of 626 works, and five appendices ( in German), abbreviated Anh. I–V which comprise:
From the time Köchel published his original catalogue in 1863 (now referred to as K), the dating of Mozart's compositions has been subject to constant revision. Many more pieces have since been discovered, re-dated, or re-attributed, necessitating multiple revised editions of the catalogue. Subsequent editions – especially the third edition (K) by Alfred Einstein (1937), and the sixth edition (K) by , , and (1964) – have reflected attempts to arrange the growing list of works in a more accurate chronological order, according to updated scholarship.
However, a major shortcoming of K was that there was no room to expand the strictly contiguous numbering in the main catalogue to allow for new discoveries or further reassessment of existing works. Simply creating a new sequential numbering according to the new chronology would shift most pieces to new numbers, causing confusion. For the 1937 edition (K) Einstein (following the analyses of Théodore de Wyzewa and Georges de St. Foix) reassigned some works from the original K appendices into the main catalogue by interpolating numbers with a lower-case letter suffix. In K some of these were, per intervening scholarship, returned to re-structured appendices: K. 626a K. 626a I – 64 Cadenzas by Mozart to his own keyboard concertos K. 626a II – Cadenzas by Mozart to keyboard concertos by other composers K. 626b – 42 sketches & other fragments by Mozart (replacing K Anh. II) Anh. A – Copies by Mozart of other composers' works Anh. B – Works by Mozart transcribed by others Anh. C – Doubtful and misattributed vocal (C 1–10) and instrumental (C 11-30) works
In response to the confusing renumbering between versions, and resistance by users to any further changes, the ninth edition (K) by Neal Zaslaw (2024) explicitly abandoned the goal of chronological ordering. Instead, to be more consistent with past usage, almost all works in the main catalogue that had been included in a previous edition of the main catalogue returned to the oldest number they had been given. Works newly included in the ninth edition's main catalogue were given numbers past 626, up to 721.The New Köchel Catalog (2024)‘Mr. Mozart’ finishes comprehensive catalog of maestro’s work, David Nutt (2024)
For example, Divertimento for Wind Octet in E was renumbered multiple times: It was numbered K. Anh. 226 in K; Einstein placed it in the K main catalogue as K. 196e, between K. 196 and K. 197; K reassigned it to the 'doubtful' appendix C as K. Anh. C 17.01; K reverted to Einstein's number K. 196e (though it is still considered a doubtful work). Some works in Anh. A have been identified since 1965 as by Leopold Mozart. Many works in Anh. C have since been more reliably assigned to other composers, or to Mozart himself.
+ Editions of Köchel's catalogueEditionYearEditorsNote11862Ludwig von KöchelOriginal21905Limited revision: mostly addition of pieces that had since come to light31937Alfred Einstein41958Unchanged reprint519616196471965Unchanged reprint8198392024Neal ZaslawChronological ordering abandoned; works no longer renumbered
List of existing Mozart compositions To maintain as much of the original K-numbering of the list as possible, while re-ordering in the revised, chronological sequence, letters were added to the new numbers. The following list shows the latest edition (K), Köchel's original designation (K), and the sixth edition (K). Other addenda and supplements to the catalogue are marked . (This has been abbreviated to 'Anh.' in the list below.)