Frequently late Neolithic and early historic (Xia/Erlitou) jades are reworked in Shang or Western Zhou eras from one shape to another, in particular from dao-blade to gui-blade and sometimes vice versa. The reworking of this blade is identified by the different location of the perforated holes, both of which are drilled from one side only. This reworking suggests a date to a post-Erlitou and early Shang context. Comparable blades of similar stone have been published; one in the collection of Mr. and Mrs. Richard C. Bull, included in the exhibition, Arts of the Chou Dynasty, Stanford University Museum, February 21-March 28 1958, no. 18. Another in the collection of Mrs. Rafi Y. Mottahedeh, was included in the O.C.S. exhibition, Chinese Jade throughout the ages, Victoria and Albert Museum, London, 1 May-22 June 1975, no. 27.