The Go-Between
Tsushima is closer to Korea than to Japan. On clear days, you can see Busan from its northern shore. For the Sō clan, who governed the island for centuries, this geography was both curse and opportunity. Too remote to matter in Japanese politics, they made themselves indispensable as brokers—the only channel through which Japan and Korea could officially communicate.
The arrangement suited everyone. The Tokugawa shoguns could maintain their policy of managed contact while still gathering intelligence on continental affairs. The Joseon court could conduct diplomacy without appearing to submit to Japan. And the Sō clan grew rich on the trade that flowed through their hands: Korean ginseng and cotton heading east, Japanese silver and copper heading west.
The Waegwan
The system's beating heart was the waegwan—a Japanese trading compound on Korean soil, near present-day Busan. Think of it as Dejima in reverse: a controlled space where several hundred Japanese merchants lived under Korean supervision, their movements restricted, their trade regulated, their presence tolerated but contained.
For over two centuries, this arrangement held. The boundary between Japan and Korea wasn't a line on a map—it was Tsushima itself, an island-sized zone of managed ambiguity where goods, information, and people crossed under careful watch.
The Modern Border
The system transformed in the late nineteenth century. Japan's Meiji government had no patience for the old brokerage arrangements. The Sō clan lost their monopoly. Korea, opened to international trade through treaties negotiated in the 1870s, was progressively integrated into Japan's sphere of influence.
The flexible borderland became a hard line. Tsushima, once the essential go-between, became a backwater—a place to pass through rather than a place where worlds met. Today, Korean tourists arrive by ferry to shop for bargains. Few know they're walking on ground where, for centuries, two nations conducted their most sensitive business.