It’s a big day for fans of experimental music and/or people with a lot of time on their hands, as the Associated Press reports that a chord just changed in a 639-year-long performance of an organ composition by John Cage for the first time in nearly seven years. The score for Cage’s 1987 work “Organ2/ASLSP,” or “As Slow As Possible,” consists of eight pages of music to be played … extremely slowly. And while a typical performance would last maybe an hour, the John Cage Organ Project is taking that “as slow as possible” directive very seriously.

Following a 1997 conference of musicians and philosophers, this performance of “ASLSP” began on September 5th, 2001, which would’ve been Cage’s 89th birthday, at the St. Burchardi Church in Halberstadt, Germany. It’s played on a special organ built specifically for this piece, with a compressor in the basement blowing air into the pipes to create a continuous sound. After a seventeen month-long pause, the first actual chord was played on February 5th, 2003. If all goes according to plan, the performance will end in 2640.

Soprano singer Johanna Vargas and organist Julian Lembke manually changed the chord on Saturday, drawing hundreds of fans to witness the event. Typically, thousands of visitors make the pilgrimage to Halberstadt to witness a chord change, but the number of guests allowed into the church was limited this year due to the coronavirus pandemic. The next chord change is scheduled for February 5th, 2022. Organizers say the performance is “one of the slowest realizations of an organ musical piece.”