In C is an aleatoric musical piece composed by Terry Riley in 1964 for any number of unspecified performers, but preferably 35 or more. As its title suggests, it is in the key of C, the simplest key to perform on the piano. It is a response to the abstract academic serialist techniques used by composers in the mid-twentieth century and is often cited as the first minimalist composition.

In C consists of 53 short, numbered musical phrases; each phrase may be repeated an arbitrary number of times. Each musician has control over which phrase he or she plays: players are encouraged to play the phrases starting at different times, even if they are playing the same phrase. The performance directions state that the musical ensemble should try to stay within two to three phrases of each other. The phrases must be played in order, although some may be skipped. As detailed in some editions of the score, it is customary for one musician ("traditionally played by a beautiful girl," Riley notes) to play the note C (in octaves) in repeated eighth notes. This drone functions as a metronome and is referred to as "The Pulse."

In C has no set duration; performances can last as little as fifteen minutes or as long as several hours, although Riley indicates "performances normally average between 45 minutes and an hour and a half."

The piece begins on a C major chord (patterns one through seven) with a strong emphasis on the mediant E and the entrance of the note F which begins a series of slow progressions to other chords suggesting a few subtle and ambiguous changes of key, the last pattern being an alteration between Bb and G. Though the polyphonic interplay of the various patterns against each other and themselves at different rhythmic displacements is of primary interest, the piece may be considered heterophonic.

Recordings of the piece include:

• State University Center of Creative and Performing Arts (1968), Sony 7178
• Shanghai Film Orchestra conducted by Wang Yongji (1989), Celestial Harmonies 13026
• In C 25th Anniversary Concert (recorded 1990, released 1995), New Albion 71.
• Bang on a Can (1998/2000), Cantaloupe 46243.
• Acid Mothers Temple & The Melting Paraiso U.F.O. (2002), Squealer 37.

External link

• OtherMinds.org Scores: In C by Terry Riley