Prepared piano

A prepared piano is a piano that has had its sounds temporarily altered by placing bolts, screws, mutes, rubber erasers, and/or other objects on or between the strings. Its invention is usually traced to John Cage, who used the technique in his dance music for Bacchanale (1940), created for a performance in a Seattle venue that lacked sufficient space for a percussion ensemble. Cage has cited Henry Cowell as an inspiration for developing piano extended techniques, involving strings within a piano being manipulated instead of the keyboard. Typical of Cage's practice, as summed up in the Sonatas and Interludes (1946–1948), is that each key of the piano has its own characteristic timbre, and that the original pitch of the string will not necessarily be recognizable. Further variety is available with use of the una corda pedal.