Where is the ancient North Sea?

In ancient China, Beihai sometimes referred to a certain water area and sometimes a place name.

1, as the name of water area, has great differences in different historical periods and contexts: Beihai was often called Bohai Sea or even Yellow Sea in the pre-Qin period, just as Mencius said, so was Taishan Beihai; Beihai in Han Dynasty refers to Lake Baikal or some lakes in Central Asia, but it also refers to the Yellow Sea and Bohai Sea.

2. After the Han Dynasty, Beihai was a county name in Shandong Province, and its jurisdiction changed from generation to generation. Beihai County in Han Dynasty was located near Weifang today.