 Nevertheless, the kingdom survived for roughly a century, benefiting from sea trade, and from the advantageous location of Ōzato Castle, situated atop tall bluffs, with an inlet from the sea and its own dedicated dock.Though its ports were not nearly as active as Naha, the chief port of Chūzan, the kingdom enjoyed its share of trade with Southeast Asia, China, and other nearby powers.Chūzan entered a tributary relationship with Ming Dynasty China in 1372.