Stamp designer Shao Bolin (right) and oil painter Jin Shangyi visit Shao's retrospective exhibition in Beijing. [Photo by Jiang Dong/China Daily]

"Because there was not a suitable studio, the bells were transported to a military base nearby and placed in an open-air auditorium. We began to take photos early at night, and the set was heavily guarded by soldiers."

A sound engineer also went with Shao to record the sounds of the archaic bells. "When we were to record, we heard toads in a lake nearby croaking loudly. We had to stop, and waited until midnight when the toads stopped making sound."

A record of a Tang Dynasty (618-907) song played with the chime bells was included in the stamp kit, allowing collectors to appreciate the stamp while enjoying the profound sound of a musical instrument made centuries ago.

The photo, the stamp and the small record of the archaic bells were all on show at the exhibition.