They are a type of ewer which was used for pouring rice wine at ritual banquets, and often deposited as grave goods in high-status burial.
The Ritual wine server (guang), Indianapolis Museum of Art, 60.43 is a fine example from about 1100 BCE.
According to Robert Bagley, this lid is the chief idiosyncrasy, or characteristic, of the guang, for it is where the largest relief and decoration often takes place.
[3] While this decor is significant in the meaning behind these works, the animal and fantastic creature ornamentation does not have an exact intended purpose for the bronzes, and is still left to interpretation.
[5] Some guang lids also depict animals, typically birds, at the back of the vessel facing or transitioning into the handle.
[8] This flange can be the central divider of a taotie, a mask-like creature motif with curving horns and two dragon-like bodies stretching out to its sides.
The earliest account of guang vessels comes from late in the Shang dynasty, during the Anyang Period, spanning from c. 1300-1046 BCE.
[11] In the Qi Guang vessel from approximately the same time period, the decoration has been compartmentalized and unified in style, which utilizes conventional motifs of bird, dragon, and other animal imagery.
The Western Zhou dynasty is the final period in which guang vessels are known to have been made, due widely to the Ritual Revolution which occurred in the late Western Zhou dynasty, ultimately reducing the number of wine vessels being made.
From late Shang to early Zhou dynasty, the number of characters per inscription increased on these bronze vessels.