Today at St Burchardi Church in Halberstadt, a town at the feet of the Harz mountains, an organ playing one of the longest-running concerts in the world, will change chord. The performance of John Cage's composition Organ²/ASLSP As Slow as Possible is scheduled to last for 639 years, finishing in 2640.
The last time the performance saw a chord change was two years ago, the 16th since it began over 20 years ago. The only performance that is forecast to last longer than this is Jem Finer's Longplayer piece for singing bowls. It began two years earlier at the Lighthouse in Trinity Buoy Wharf, London and is due to finish in 2999.
John Cage composed As Slow as Possible for piano in 1985 and adapted it for the organ two years later. The instruction in the title isn't matched by an official exact tempo, but its premiere in Metz lasted just over 29 minutes.
The project at Halbertstadt uses a mechanical organ, in which an electronic wind machine pushes air into the pipes. Rather than a human operating the instrument, sandbags press down the keys. The performance began in 2001 and was followed by a 17-month silence, as instructed in the scaling of the score. The first chord was heard in 2003.
