Catalogues of classical compositions

Opus numbers

• Some composers used it for certain genres of music but not for others.
• Some composers gave opus numbers to some of their early compositions but abandoned the practice after some time.
• Some used it in a very erratic manner, or were subject to the wishes of their publishers, who for commercial reasons often presented works with opus numbers that bore little relationship to their place in the chronological sequence of the composer's works. In cases such as Schubert and Dvořák, one opus number could refer to a number of different works; or a single work could appear under different opus numbers.
• Some composers abandoned their early compositions and restarted the opus numbering sequence. Some did this more than once. For example, Bartók three times started numbering his works with opus numbers. He stopped the system in 1921 because of the difficulty of distinguishing between original works and ethnographic arrangements, and between major and minor works.
• A few composers allowed superstitious considerations to override chronological specificity in numbering: Massenet, for this reason, published an "Opus 12B" but not an "Opus 13."

Comprehensive catalogues

• the BWV numbers allocated to Johann Sebastian Bach's works in the Bach-Werke-Verzeichnis developed by Wolfgang Schmieder. They are also sometimes referred to by their S numbers
• the K numbers allocated to Wolfgang Amadeus Mozart's works in the Köchel catalogue, created by Ludwig Ritter von Köchel. In Germany and other parts of Europe, the symbol used is KV, for Köchel-Verzeichnis
• the numbers allocated to Franz Schubert's works in the Deutsch catalogue, developed by Otto Erich Deutsch

Thematic catalogue

Multiple catalogues

• For Domenico Scarlatti, the Longo catalogue was in use from 1906, and although it has become generally superseded by the 1953 Kirkpatrick catalogue, L numbers are still seen in references. In 1967, Pestelli created a third catalogue, which has found acceptance in some places. Because all three symbols are often encountered, there is a concordance to help navigate between them.
• Beethoven's works can appear with an opus number, a WoO number, a Hess number or a Bia number. Until 1955, the opus numbers that appeared in the Beethoven Gesamtausgabe were used exclusively, but this edition omitted a large number of works. In 1955, Georg Kinsky and Hans Helm produced a listing of works that had not been given opus numbers, and gave them WoO numbers. This listing is often referred to as the Kinsky Catalogue. In 1957, Willy Hess produced a new catalogue of Beethoven's unpublished works, which included all or most of the Kinsky Catalogue as well as other pieces; Hess numbers were allocated to this sequence of works. In 1968, Giovanni Biamonti produced the Biamonti Catalogue, which sought to combine and update all pre-existing catalogues. Bia numbers relate to this catalogue.
• * Note: The WoO symbol has also been used to classify some other composers' works that were not given opus numbers, such as certain works by Mendelssohn, Schumann and Brahms.
• In Chopin's case, at least three latter-day catalogues vie for prominence: Maurice J. E. Brown ; Krystyna Kobylańska ; and Józef Michał Chomiński, whose catalogue is segmented into six parts, each part utilising a different letter. Hence, a work of Chopin can be referred to by its opus number and/or a catalogue number preceded by one of eight letter symbols.
• The cataloguing of Bartók's works is similarly complex. Bartók assigned opus numbers to his works three times. He ended this practice with the Violin Sonata No. 1, Op. 21 in 1921, because of the difficulty of distinguishing between original works and ethnographic arrangements, and between major and minor works. Since his death, three attempts—two full and one partial—have been made at cataloguing. The first, and still most widely used, is András Szőllősy's chronological Sz numbers, from 1 to 121. Denijs Dille subsequently reorganised the juvenilia thematically, as DD numbers 1 to 77. The most recent catalogue is that of László Somfai; this is a chronological index with works identified by BB numbers 1 to 129, incorporating corrections based on the Béla Bartók Thematic Catalogue.

  List of catalogues