How did the Yap empire connect Yap with surrounding coral atolls?

In pre-European times, Yap served as the center of a cultural area that extended across the central Caroline Islands. The Yapese connected with surrounding coral atolls through a well-developed system of trade and social exchange.12

This relationship was characterized by the following dynamics:

• Resource Exchange: High islanders on Yap provided goods that were more easily obtained on their fertile land, most notably turmeric, which was used for medicinal purposes, cosmetics, and as a component for body paint. In return, low islanders from the atolls provided handicraft products, such as shell beads, plaited pandanus mats, and coarse cloth woven from banana or wild hibiscus fiber.2
• Social Bonds: Trade was frequently conducted between specific partners who regarded one another as distant relatives.2
• Mutual Aid: A critical function of this interisland network was to provide low islanders with essential aid and temporary dwellings when their atolls were devastated by periodic cyclones.2
• Navigation: The Yapese were among the few high-island peoples who practiced significant navigation on the open seas, allowing them to maintain these connections.3