 As with vocal score (below), it takes considerable skill to reduce an orchestral score to such smaller forms because the reduction needs to be not only playable on the keyboard but also thorough enough in its presentation of the intended harmonies, textures, figurations, etc.Sometimes markings are included to show which instruments are playing at given points.While piano scores are usually not meant for performance outside of study and pleasure (Franz Liszt's concert transcriptions of Beethoven's symphonies being one group of notable exceptions), ballets get the most practical benefit from piano scores because with one or two pianists they allow the ballet to do many rehearsals at a much lower cost, before an orchestra has to be hired for the final rehearsals.