Pottery Mould for Bronze Arrowheads, Early Shang Dynasty (c. 16th-14th centuries BC), unearthed at Erligang, Zhengzhou, Henan Province, 1953. It is exhibited in the section of Exhibition on life, production in Xia, Shang and Western Zhou dynasties, an exhibition of Ancient China in the National Museum of China. [Photo by Xu Lin / China.org.cn]