By Tony Czuczka
The Associated Press

HALBERSTADT, Germany - First there was silence - 1 1/2 years of it. But that was just a brief lead-in for Friday's playing of the opening notes in what's planned as the world's longest concert, a 639-year piece being performed in a former church in east Germany.

With 72 years already mapped out, the concert inspired by the American avant-garde composer John Cage challenges the creativity of future generations to keep the music playing.

"This is a project that conveys optimism," said Michael Betzle, a businessman who helps run the private foundation behind the concert. "When you start something like that, you're counting on people's creativity 200, 300 years down the road."

The three notes played Friday - G sharp, B and G sharp - are the debut for an organ built for Cage's music, with keys being held down by weights and with organ pipes to be added over the years for new notes.

20 minutes stretched out

The project, driven by a group of German music experts and an organ builder, is centered around a Cage piece called "Organ2/ASLSP" - or "Organ squared/As slow as possible."

An unused church in Halberstadt, a town with a proud organ-building tradition dating to the Middle Ages, serves as the performance space and the inspiration for extending the piece over centuries.

As the idea took shape in 2000, backers counted back to the 1361 inauguration of a famous organ in the Halberstadt cathedral - 639 years earlier.

They then stretched Cage's piece from a 20-minute piano concert to last just as long.

The concert actually began Sept. 5, 2001, the day Cage - who died in 1992 - would have turned 89.

But since the composition starts with a rest - music language for silence - the only sound inside the church has been the tap-tap of the organ builders and the sound of air driven through the pipeless organ by an electric fan.

It's a concept that Cage surely would have appreciated. A student of avant-garde composer Arnold Schoenberg, he once wrote a piece consisting of 4 minutes and 33 seconds of silence.

Other Cage innovations included "prepared piano" performances, using a standard piano altered with noisemaking items like screws and wood placed between the strings.

Like with Cage, stretching the meaning of music is on the minds of the Halberstadt organizers.

"Others have eternal flames," Betzle said. "We have the eternal sound - or at least 639 years."

The foundation is seeking sponsors to fund the organ's estimated $215,000 cost. People can choose a year to sponsor with a $1,080 donation.

Next notes in 2004

Anyone who missed Friday's gala has plenty of time to hear the opening E major chord, which will play continuously through August 2005. The next notes will be added in July 2004.

German music scholar Heinz-Klaus Metzger, who knew Cage and was one of the project's advisers, said he thought his friend would have loved the concept.

"I imagine he would have been amazed," Metzger said. "Then he would have said: `Yes, do it.' "