Sō Sadamori

Sō Sadamori was a military commander of the early to mid-Muromachi period. He served as the shugo daimyō of Tsushima and was the ninth head of the Sō clan.

Multiple dates have been suggested for his birth, but most people are inclined to say that it was around 1385. The boy's name was Miyatsukumamaru and he has also been referred to as Hikoroku and Uma. After his father died in 1418, he became the head of the family when he was still rather young and used his childhood nickname. Because he was so young then, the power within the family, by and large, was exercised by Hayata Saemontarō, who was a very powerful member of the various pirate communities in the area. The fighting between Japanese and Joseon forces during the Ōei Invasion of Japan occurred in 1419, with neither side claiming a clear victory. Although he rejected the Joseon demands and attempted several times to warn their envoys about an impending storm, he was not able to broker a truce but did help to end the hostilities.^[1]

In the years after these events, he worked very hard to improve the relationship between his family and the Joseon dynasty and to secure better conditions for Japanese fishermen operating in Korean waters. In 1441, he reached an agreement with the Joseon that allowed Japanese fishermen to fish in the waters around Korea, but it limited fishing at the island of Kokaku. Subsequently, he negotiated the Kakitsu Treaty, which gave him complete control over the Korean trade. He also created the Bunbiki system, which allowed the Sō clan to have a monopoly of the shipping on the island of Tsushima. However, he eventually,suffered some trouble with the Ōuchi clan, which had a rival opinion on the Bunbiki system.^[2]