English: Shang dynasty Bronze ibex-headed knife 13th-11th century

Such knives may be the result of contacts with northern people. (Shang knife British Museum (in en). www.britishmuseum.org. "In subsequent centuries such knives were more popular with peoples of the northern zone than with the Shang and Zhou inhabitants of Shaanxi and Henan. It is, therefore, possible that even in the Erlitou period such knives illustrate contact with northern peoples. Alternatively, the spread of Erligang culture may have taken such knives from central Henan to the periphery.")((1995) Traders and raiders on China's northern frontier: 19 November 1995 - 2 September 1996, Arthur M. Sackler Gallery, Seattle: Arthur M. Sackler Gallery, Smithsonian Inst. [u.a.], pp. 35−36 ISBN: 978-0295974736. "Enough northern bronze knives, tools, and fittings have been recovered from royal burials at the Shang capital of Anyang to suggest that people of northern heritage mingled with the Chinese in their capital city. These artifacts must have entered Shang domain through trade, war, intermarriage, or other circumstances.")