Though a coastline of some 15,000 kilometers from Korea to Vietnam has historically bounded and defined it, China has a reputation as a continental, not a maritime, empire. This reputation is not entirely misconceived, deriving in part from the sheer size of the land empire, which over two millennia has ballooned into the Eurasian interior to such an extent that it has steadily driven down the ratio of land area to coastline. The Chinese have regularly and consistently interacted with—traded with, escaped into, invaded and been invaded by—the peoples and territories to the north and the west, and most Chinese regimes have formed through the dynamic of that interaction. This in turn has fed a potent myth of cultural origination in the loess hills along the upper reaches of the Yellow River, a myth that continues to persuade the Chinese that they are children of the yellow earth, not progeny of the blue ocean. Historians for three millennia have followed suit, writing China's history as an unbroken sequence of land-based dynasties whose capitals are never port cities and whose military heroes have commanded armies, not armadas.

With this idea has coexisted another reality. For, as state and economy have historically expanded toward the interior away from its coastline, simultaneously they have extended in the opposite direction out to sea.