Ryukyu trade in the 1340s and the Sanzan division

Timeline

1. 1341–1345Shuri · Kingdom of ChuzanThe Kingdom of Chuzan, centered on Shuri, maintained trade with Kyushu and Korea via coastal routes, exporting sulfur and shells and importing ironware and ceramics. Hokuzan and Nanzan likewise maintained their own independent port-town networks.
2. 1343–1348Amami sea route · East China SeaRyukyu merchant ships sailed via the Amami Islands to ports such as Hakata in Kyushu, participating in East Asian coastal trade. Amid political upheaval in late Yuan China, some Ryukyu merchants still tried to maintain contacts with Chinese ports, obtaining porcelain and currency.
3. 1349–1350Okinawa main island · Okinawa main islandBy 1350 the trade networks of the three kingdoms covered the main ports of the East Asian coast, with steady exports of sulfur, shells, and timber. This foundation created the conditions for Shō Hashi's unification of the three kingdoms in the 15th century and the subsequent flourishing of tribute trade with the Ming.