Ko-Ko is a landmark bebop composition by Charlie Parker, first recorded on November 26, 1945, at WOR Studios in New York City for Savoy Records. The piece is a contrafact built on the chord changes of Ray Noble's "Cherokee," with Parker creating an entirely new melodic line over that harmonic framework. The tune arose out of practical necessity: producer Teddy Reig balked at paying royalties for "Cherokee," so Parker improvised a fresh melody on the spot, transforming what began as a workaround into one of the most historically significant recordings in jazz. The composition features a striking 32-bar introduction with alto saxophone and trumpet in unison octaves, brief solo breaks, and passages in thirds and fourths before the solos begin. Parker's approach on Ko-Ko embodied a principle that became central to bebop: deriving melody from upper chord extensions rather than traditional scalar passages, a discovery Parker described as a kind of personal rebirth, saying "That's when I was born." The original recording featured Parker on alto saxophone alongside Miles Davis and Dizzy Gillespie on trumpet, Curly Russell on bass, and Max Roach on drums. Parker's solo on the recording became one of the most studied saxophone solos in jazz history, noted for its extraordinary speed, recurring motivic patterns, and quotations including a reference to Alphonse Picou's clarinet showcase "High Society." In 2002, the Library of Congress added Ko-Ko to the National Recording Registry, recognizing its enduring cultural importance.