Bronze circular plaques of this type with a horizontal bar set to the reverse are called pao (bubble) in Chinese. They could be used as ornaments to decorate horse bridles or to adorn the carriage of a chariot - usually along the handrails or the sides of the base. Compare a group of bronze ornaments of this type made in various designs, excavated from a late Shang dynasty tomb at Xiaotun village, Henan province, exhibited in Charioting in the Shang Dynasty: Artifacts from the Horse-and-Chariot Pits at Hsiao-t'un, National Palace Museum, Taipei, 2006, p. 51. The bird motif on the present ornament is also on a Shang dynasty bronze chariot fitting, possibly a yoke finial, cast with a closely related bird on the top, in the Palace Museum, Beijing, published in The Complete Collection of Treasures of the Palace Museum. Bronze Articles for Daily Use, Hong Kong, 2006, pl. 1.