Music Discovery Requirements

II.E Musical Works: Musical Key/Range

Original key can be useful for identifying tonal works of Western art music, particularly when the work has a generic title and the identifying number (such as an opus, work, or thematic catalog number) is unknown, absent from the cataloging data, or wholly non-existent.

Edition statements may contain information on the key or voice range. The manifestation may not identify whether such statements refer to the original key/range or a transposition, so best practice is to simply include edition statements in indexing and display.

The musical note "a" presents special considerations in systems which consider it a stop word. Phrase searching must be configured so terms that otherwise function as stop words must be searched as terms when enclosed in quotes or as part of phrases within quotes. With this capability, a search on “a major” will return bibliographic records containing the string “a major” (a musical key) rather than “major” alone. See IV.E for more details.

Another consideration for searching for works with known key is the exclusive use of the symbols for music sharps and flats in uniform/preferred titles and the potential for symbols, rather than spelled out terms, to be used in descriptive fields. In some older data, the pound sign (#) is used as a replacement for the musical sharp, and the lowercase “b” is used as a substitute for the musical flat. One possible solution is to associate the search terms “sharp” and “flat” with their respective symbols and substitutes, and vice-versa. This may result in some false hits, especially for searches unrelated to music, but this could be mitigated by prompts to include or exclude musical symbols from searches. For example, a message along the lines of “including results for ♯ (musical sharp sign). Search only for the word sharp" (linked to a search excluding the sharp sign) would provide a solution for searches containing numerous false hits. Another option is a feature that allows users to select from a set of frequently used symbols or diacritics. Regardless of search functionality, the system must allow entry and display of the symbols for musical sharps and flats in all fields of bibliographic and item records.

An additional field that contains musical key information is MARC 031 in bibliographic and authority records. Defined for recording musical incipit[1] in ordinary ASCII characters, it can be used for any material containing music. While $p contains the incipit itself, $r is used to record the key or mode. Therefore this field could potentially be used for searching by key; equally beneficial would be the capability to convert the coded incipit to musical notation for public display and searching. However, like many other MARC fields, 031 has not been coded regularly in bibliographic or authority records.[2] The RISM interface provides an example of user-friendly searching via an on-screen piano keyboard, albeit based off the Plaine & Easie Code, which is not widely used in United States library MARC cataloging.[3]

MARC 384 is defined to record key information, including a first indicator to designate original or transposed key. Though defined in both bibliographic and authority formats, it is more commonly applied to authority records.[4]

Key and range can also be attributes at the expression level, as further discussed in III.H.

Recommendation: Index and display musical key and range. Ensure that “a” (frequently a stop word), can be forced to be searched as a term. Ensure that the musical sharp and flat symbols can be entered, displayed, and searched. Evaluate data for feasibility of use as a facet. Explore the use of MARC 031 in bibliographic and/or authority records.

Index and Display (Bibliographic/Descriptive Metadata):

MARC: 130 $r; 240 $r; 7xx $r; 031 $r Key for music

MARC: 250 Edition Statement

MARC: 384 [Musical] Key (generate display label based on first indicator)

Dublin Core: No field defined to include musical key/range information. Examine data set for whether "description" or possibly "coverage" may contain this data.

EBUCore: No field defined to include musical key/range information.

MODS: No field defined to include musical key/range information.
PBCore: No field defined to include musical key/range information.

BIBFRAME 2.0: Properties: bf:musicKey

Facets/Limits (Bibliographic/Descriptive Metadata):

In a music-specific interface, a facet or limit for musical key could be useful. However, in most legacy data, key is rarely recorded for distinctively-titled works, so such a facet would be far from comprehensive. MARC 384 can be coded for either work (original) key (in bibliographic or authority records) or expression key (in bibliographic records). Key in MARC $r in MARC 130, 240, or 7xx may be misleading in cases of arrangements. Therefore, distinguishing between work key and expression key could be very problematic in facets/limits.

MODS: note type="key"

Related MARC Authority Fields:

MARC: 031; 100 $r; 130 $r; 384

[1] Musical incipit is the opening fragment of a musical work. The incipit helps to identify the work.

[2] The Moravian Music Foundation is one institution which regularly codes 031. See OCLC numbers: #923024892, #905230517, and #905237411 for examples.

[3] Plaine & Easie Code. Maintained by the International Association of Music Libraries and the Répertoire International des Sources Musicales, accessed August 25, 2017, RISM OPAC. Répertoire International des Sources Musicales, accessed Aug. 25, 2017,

[4] MARC 384 is not repeatable in either bibliographic or authority format. As a result, common practice is to not include 384 in bibliographic records for manifestations containing multiple works. MARC 384 allows key to be recorded for expressions that are transpositions (key other than the original work); currently RDA provides instructions for recording key at the work level (original key) only.