The three clocks are part of the largest collection of musical clocks worldwide and were made by Western artisans, primarily British. The first three clocks were transported to Utrecht, central Netherlands, in early February to be restored by the Utrecht's Musical Clock and Street Organ National Museum.

Twenty musical clocks are to be exhibited in the museum in 2010, marking the first time Chinese state treasures will be displayed to the public outside Chinese territory.

"The clocks came into the possession of successive Chinese emperors from the 17th century onwards," the museum's curator Bob van Wely said.

Van Wely had always known the Forbidden City owned a beautiful collection of musical clocks. When he traveled to Beijing, he discovered that Dutch expertise could be put to use.

"After the last emperor was deposed and the Forbidden City was transformed into a museum in 1925, no new clockmakers and restorers were educated in China," he said.

Van Wely proposed that the Utrecht museum would help the Chinese restore several clocks and teach them how to do it themselves. In exchange, the Chinese would lend some pieces to the Utrecht museum for an exhibition.