This blade derives from the tool type of knife that was used to cut and saw during the Neolithic era of ancient China. The blade may have been reworked from an earlier shape due to the rectangular bracket located on the blade's upper edge. It is Erlitou in date due to its symmetry and quixotic lack of more than one hafting hole along the upper long edge of the blade. An undecorated, symmetrically trapezoid jade dao excavated at Erlitou is published in Kaogu 1975:5, pl. 8:9. Closest in type and shape to the Sackler piece is an example from the American Museum of Natural History included in the exhibition, Ritual and Power: Jades of Ancient China, China Institute, New York, 1988, and illustrated by E. Childs-Johnson in the Catalogue, fig. 46