Shang city in Yanshi built in 1600BC was built earlier than Shang city in Zhengzhou built in 1580BC, so Shang city in Yanshi is the boundary of Xian and Shang dynasties.

• 偃师商城始建于公元前1600年，郑州商城始建于公元前1580年，前者早于后者，偃师商城遂成为夏商分界的界标。