Köchel

Köchel, short for Köchel-Verzeichnis, is the standard catalog of Wolfgang Amadeus Mozart's works. Compiled by the Austrian musicologist Ludwig Ritter von Köchel and first published in 1862, the catalog assigns a Köchel number to each work, providing a concise reference used in musicology, performance, and publishing.

The catalog aims to organize Mozart's oeuvre by genre and, where possible, by date of composition. Each entry includes the work's title, key, instrumentation, and date of composition when known, along with sources. The numbers—Köchel numbers—are widely cited in scholarly editions, concert programs, and recordings, and they help distinguish pieces with similar or multiple titles.

Origin and revisions: Köchel's initial edition was expanded and refined through successive revisions as scholarship advanced. The work has undergone multiple updates, with the current standard reflecting later research. While generally stable, some entries are refined or re-evaluated, and certain works are listed in an Anhang (appendix) for doubts about authenticity or uncertain dating.

Impact: The Köchel catalogue established a canonical reference system for Mozart's works that persists in musicology, libraries, and education. It lays the groundwork for modern editions and scholarly work, and remains the basis for cataloging Mozart's compositions worldwide. The catalog also aids in identifying spurious works and tracking revisions across scholarly sources, ensuring a common framework for studying Mozart’s output.