These are percussion musical instruments unique to ancient China. The zhong are made of bronze while the qing generally of stone. They may be played either individually or in groups. In the latter case, they are hung in rows on wooden racks and known respectively as bianzhong and bianqing. Struck with wooden hammers, they produce melodious sounds of various notes. In their time, they were the important instruments played - either in solo performance or in ensemble or as accompaniment - during imperial audiences, palace banquets and religious ceremonies.