A variety of climatic factors determined what occurred within the boundaries of the East Asian Sea during the age of sail. Important characteristic such as the “deep structures” of the seas were also determining factors that shaped the routes sailors charted and the maritime policies set up by governments. In many cases in China and elsewhere, rulers, sailors, and sea merchants had to adjust to all of these climatic flows. This does not mean to deny the importance of these deep structures. However, it is important to note that the sea space could be shaped by human hands at many levels. This sea space could be conceptually modeled by a group of intellectuals, with little, if any, experience going aboard and only a very limited knowledge of the waves and the winds and their impact on navigation. Regarding the naval setting along the coast of China, the reason why some of these port cities were strategically important depended, to a significant extent, on other factors and limitations in addition to the wind and the waves. In other words, it must be emphasized that the East Asian Sea, like many other maritime spaces, was constantly shaped by both human and non-human factors.