Through the East Asian waters its neighbouring countries have since early times on maintained networks of trade and exchange relations. Historically, these waters constituted not only a kind of border or natural barrier but from very early times on also a medium facilitating all kinds of exchanges and human activities, a medium through which in particular private merchants but also governments and official institutions established contacts with the world beyond their borders. The seas were sometimes considered a barrier but above all a contact zone, a medium that despite its dangers and difficulties enabled people to establish and maintain manifold exchange relations.This article intends to provide a general outline of the historical role and significance of East Asian maritime space from its origins to approximately 1800, including the East China Sea, the Bohai Sea, the Yellow Sea (Huanghai), the southern section of the Japanese Sea, and parts of the South China Sea (now usually called Nanhai). It focuses especially, although not exclusively, on China’s traditional treatment of and reference to this maritime realm. Also in order to maintain the spatial concept operable, we have decided to call this maritime space the “China Seas”.