Organ²/ASLSP (As SLow aS Possible) is a musical piece composed by John Cage and is the subject of the slowest and longest-lasting musical performance yet undertaken. It was originally written in 1987 for organ and is adapted from the earlier work ASLSP 1985; a typical performance of the piano piece lasts for about 20 to 70 minutes. In 1985, Cage opted to omit the detail of "exactly how slow the piece should be played". The current organ performance of the piece at St. Burchardi church in Halberstadt, Germany, began in 2001 and is scheduled to have a duration of 639 years, ending in 2640.
The score consists of eight pages, the tempo of which has been stretched to fit the wanted duration of 639 years.
The piece was commissioned by The Friends of the Maryland Summer Institute for the Creative and Performing Arts as a contemporary requirement for a piano competition. Cage employed an open format mainly to ensure that no two performances would be the same, providing the judges a break from the monotony of most competitions.
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It all ends on the 27th Century