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A vocal score or piano-vocal score is a music score of an opera, or a vocal or choral composition with orchestra such as an oratorio or cantata, in which the vocal parts are written out in full but the accompaniment is reduced and adapted for keyboard (usually piano). The music is usually reduced to two staves; however, more staves, a second keyboardist (piano-four-hands), or a second keyboard part can be added as needed.
There are two main types of piano-vocal scores. The first kind consists of those scores created by a composer in the process of composing, usually as a harmonic map of the piece to be later orchestrated. The second category includes scores that are arrangements or transcriptions made after the completion of the work, usually by someone other than the composer.
Piano-vocal scores are generally created for purely practical reasons, such as rehearsing of singers or studying the compositional structure of the score. Before the widespread availability of sound recordings, piano-vocal scores were also sold for small-scale or home performance of the piece, where a full orchestra would not be practical.