]BCE) and Erligang (c. 1500–1,400 BCE) periods.Bronze objects dated to the last period of existence of Zhukaigou culture c. 1500 BCE point to native production of a mixed complex of bronze objects that included typical "Northern Zone" items like daggers, with typical Shang "ge" (戈) dagger-axes, and knives that reveal both Shang and northern features.