ISMN is a unique identification of printed music, published for sale, hire or free distribution in score or parts.
(Publications which are NOT given ISMN numbers include books on music, sound- and video recordings and series and periodicals as a whole)
Each number consists of 13 figures:
- a number code 979-0- separating it from other standard numbers (ISBN and ISSN)
- a number identifying the publisher
- a number identifying the title
- a control number which identifies a mistake in the numbers
The Danish ISMN office is housed by The Music and Theatre Department, which is in charge of the distribution of ISMN numbers to Danish publications. The international agency is responsible for the ISMN system, its standards and use.