Music Terminology Reference

Opus, Kochel, RV... What does it all mean?!?

Have you ever wondered who or what the Kochel number is when mentioned in association with Mozart, or a BWV number for Bach? These and many more will be explained -- read on, fearless visitor!

What is an opus number?

Opus is a Latin word for "work". In music, the word is usually followed by a number. The assignment of opus numbers is extremely inconsistent from one composer to another. In some cases, publishers determined which works were given which numbers. It was only a matter of time before confusion arose. Some composers refused to number their own works for a variety of reasons. Sometimes, there is a number that follows an opus number. In this case, the opus number refers to a group of works and the second number indicates which particular piece within that group is represented. A good example is Beethoven's Opus 27, No. 2. Opus 27 was a group of sonatas for the piano. No. 2 in that group was Sonata #14 now known as "Moonlight".

What is a Kochel number?

Kochel is associated with Mozart. Ludwig von Kochel was a botanist and mineralogist who greatly admired Mozart's music. In the mid 1800's, he undertook the arduous task of attempting to catalog the compositions in chronological order. This was a tough challenge for two reasons: Mozart was so prolific during his short life that there would be no way of knowing for certain that all of his compositions had been located. The second challenge lay in the fact that, although Mozart was well-known in his own lifetime, he was almost constantly having to write new works to get out of money problems -- as a consequence, no particular value was placed on the preservation of each work. It took Kochel more than ten years to locate the pieces, determine the chronological order, assign a catalog number and then publish the catalog. For his efforts, he is remembered (if only indirectly) each time a Mozart work is listed.

Sometimes, you will see or hear "KV" with Mozart. This is not a separate catalog. The "V" stands for the German "Verzeichnis" (or "catalog"). So in effect KV means "Kochel Catalog". Bottom line, "K" and "KV" mean the same thing.

So How Come You Use a "K" Number with Other Composers?

The only other "K" number used with mainstream classical composers is for works of Domenico Scarlatti. The "K" in this instance means Ralph Kirkpatrick, who played harpsichord and was Professor of Music at Yale University. Using the same method as Kochel, Kirkpatrick assigned catalog numbers in chronological sequence.

At WCPE, we try to make sure to avoid confusion between the two "K" numbers by announcing a work of Scarlatti's and then saying "Kirkpatrick number ___".

Isn't BWV a German Luxury Car?

BWV is the acronym for Bachwerkeverzeichnis - a long German term which translates as "Bach Work Catalog". Like Mozart, Bach was incredibly prolific in the generation of music. Most of his works were written for a specific occasion but little value was placed on them during his lifetime. When Wolfgang Schmieder undertook the task of compiling a cohent list of all of Bach's compositions, an incredible amount of research ensued. The fruit of his labor is accepted universally as the most definitive catalog of Bach's music. No one is absolutely sure that all Bach compositions are represented in the catalog (the same problem that is presented in reviewing Kochel's compilation). Occasionally, you will find a Bach work that has an "S" number instead of BWV -- these are one and the same. Virtually all sources prefer to show BWV numbers for consistency's sake.

RV? Vivaldi had a recreational vehicle?

Vivaldi composed more than 600 concerti. An occasional wag has said that Vivaldi actually only composed one concerto and had 600 arrangements of the same piece. Nevertheless, Peter Ryom catalogued Vivaldi's work in the 1960's and 1970's. Today, Ryom's catalog is considered definitive and it is common to see RV (for Ryom Verzeichnis) numbers follow the title of a piece. This is a situation however where confusion arises because Vivaldi's publishers assigned opus numbers. Occasionally, then, you will see an opus number and an RV number.

Deutsch? Isn't that German??

Otto Erich Deutsch is associated with Schubert. He was born in Vienna in 1883 and died there in 1967. He emigrated to England in 1939 and lived there until 1953 before returning to Austria. He catalogued the works of Franz Schubert, starting in 1923 but not finishing until 1951 when the thematic catalogue was issued. Deutsch was a music historian, publisher and writer who specialized in the composers of the Vienna classical period, most notably Schubert. Among his written works are also "A Documentary Biography" of Mozart, a 680 pages volume of every document relating to the composers life (Stanford University Press 1965) and "Schubert: Memoirs by his friends" (Oxford University Press 2000).

And there are many more Thematic Catalogue Abbreviations than these! Perhaps the best work to read about this topic is: "Thematic Catalogues in Music" by Barry S. Brook and Richard Viano, Pendragon Press 1997.

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