Date: Xia (21st-16th century BCE)
Dimensions: Length 34.8 cm, Width 6.0 cm, Thickness 0.8 cm
Material: Jade
Zhang blade, as a ceremonial weapon and a symbol of its owner's supreme power and identity, may have an association with mountain worship. Black jade, or xuanyu as named in pre-Qin documents, once took pride of place in the Central Plain and the west of China.