So Yoshishige (1532-1588)
Yoshishige was a son of Sô Haruyasu and ruled the island of Tsushima in the Korean Straits. He clashed with the Matsuura and in 1587 submitted to Toyotomi Hideyoshi and initiated a failed attempt at negotiations with the Koreans, with whom he had ties through the Sô's trading endeavors. He died while these negotiations, aimed at securing passage for Hideyoshi's armies in an invasion of China, were in progress.
References
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005