The Border Islands
Throughout history, the islands of Iki, Tsushima, and the Goto chain off the western coast of Kyushu have been at the forefront of encounters and exchange between Japan and continental Asia. Tombs and temples, sites of ancient settlements and fortresses, and customs and rituals still practiced today on these border islands tell a 2,300-year story of trade, cultural interaction, and conflict.
Regular exchange among the peoples of the Japanese archipelago and those of mainland Asia across the Tsushima Strait, where Iki and Tsushima are located, is thought to have started before the beginning of the common era. The earliest written record of such interaction is found in the third-century Book of Wei, part of the Chinese historical text Records of the Three Kingdoms.
An account in the Book of Wei of envoys from the state of Cao Wei journeying via the Korean Peninsula to the Japanese kingdom of Yamatai includes descriptions of Tsushima and Harunotsuji, the capital of the ancient kingdom of Iki. The history of this mercantile hub, where the people of Iki exchanged wares and information with traders and travelers from the Korean Peninsula, China, and mainland Japan, can be explored at the Harunotsuji Special Historic Site and in the adjacent Ikikoku Museum. The early history of Tsushima is presented in detailed displays at the Tsushima Museum.
The kingdom of Iki is thought to have been conquered by forces from mainland Japan, which in the sixth and seventh centuries used the island as a staging ground for warfare on the Korean Peninsula. This coincided with the construction of hundreds of kofun burial mounds, which likely were tombs for prominent warriors. Many of the kofun remain and some are open to the public.
After Japan and its allies’ ambitions on the Korean Peninsula were ended by Tang China and the Korean kingdom of Silla in the mid-600s, Tsushima and Iki became key nodes in a network of forts and beacons established to guard against an invasion from the continent. Kaneda Fort on Tsushima was the first line of defense in this network, while the Takenotsuji mountain on Iki is thought to have been the site of a smoke beacon used to send warnings of impending foreign threats to Kyushu.
Despite the political tension, the seventh century was also a time of active peaceful exchange. From 630 onward, Japan sent regular diplomatic and trade embassies to the Tang dynasty in an effort to learn from Chinese culture and civilization. These delegations initially traveled via Iki and Tsushima, but from the year 702 adopted the shorter but more dangerous route from Goto directly across the East China Sea. There are numerous sites associated with the envoys throughout the Goto islands, including the windswept Mimiraku Peninsula from which many of their ships departed.
Exchange across the Tsushima Strait took many forms in the medieval period and during the conflict-ridden Sengoku period (1467–1568). Merchants and pirates from the border islands traded and pillaged along the Korean and Chinese coasts, and some accumulated considerable profits along with a measure of political independence. Namaike Fort on Iki was built by one particularly successful operative, while the Stone pagodas of Hinoshima in the Goto Islands serve as monuments to seafarers whose names have been lost to history.
In the 1590s, the warlord Toyotomi Hideyoshi (1537–1598) twice launched expeditions to conquer China via Iki, Tsushima, and the Korean Peninsula. Katsumoto Castle on Iki and Shimizuyama Castle on Tsushima were built as footholds for these ultimately unsuccessful attempts, which temporarily severed relations between the border islands and Korea.
Ties were reestablished in the early 1600s as a result of the efforts of the So family, the lords of Tsushima. Throughout the Edo period (1603–1867), the So held a monopoly on Japanese trade with Joseon Korea, a lucrative privilege granted in return for managing diplomatic relations between the kingdom and the Tokugawa shogunate. The Korean missions to Tokugawa Japan all passed through Tsushima, where sites such as the So mausoleum at Banshoin Temple and the Ofunae dry dock stand as testament to the prosperity brought about by the trade with Korea.
These and many other sites, customs, and artifacts on Iki, Tsushima, and Goto that convey the islands’ history of exchange with continental Asia have collectively been designated a Japan Heritage Site under the title “The Border Islands Iki, Tsushima, and Goto—The Ancient Bridge to the Continent.”
