A piano score is a type of ensemble sheet music intended solely for the piano. Like all sheet music, it is a song's written notation; a piano score tells the musician what to play and how to play it. Unlike all sheet music, however, a piano score shows not only the piano part but nearly every other part in the ensemble as well. It can be a confusing piece of sheet music; the pianist must get used to following their part closely in conjunction with the other ensemble instruments. Traditionally, this is the job of the conductor. A normal conductor's score will notate every part of the ensemble in one large book of sheet music to aid the conductor in focusing on the various instruments. A piano score, however, is handled completely by the pianist. While it may mirror the score used by the conductor, it is rarely an exact replica; the notations, after all, are intended for an actual musician in the ensemble as opposed to the person directing it.
A piano score is used in a variety of different forms and genres; it knows no boundaries of style. The type of piano score used is often based solely on the type of music or ensemble. The pianist in a large ensemble, such as an accompanying orchestra to a theatrical performance, will often use a partial piano score. This type of piano score doesn't include every single instrument, just the parts vital to the pianist's understanding of the melody and rhythm; partial piano scores (despite being only partial) are still fairly detailed. A full piano score is usually only used by smaller ensembles, though even the small ensembles revert to a partial piano score at times. Jazz musicians particularly use a partial piano score even less detailed than a large orchestra's piano score. Due to the improvisatory nature of jazz music, detailed sheet music is rarely necessary; depending on the ensemble, the sheet music functions more as flexible notes than anything else. A piano score in jazz works in this manner. It gives the pianist vital reminders about the melody, rhythm or harmony, but allows for variations on the overall theme; a piano score here will only show what truly needs to be shown.
___________________________
