Oei Invasion

The Ôei Invasion was an attack on the island of Tsushima launched in 1419 by Joseon Dynasty Korea.

Though controlled by the Sô clan for centuries, Tsushima (K: Daemado) was believed by the Joseon court to have been Korean territory in ancient times, and to be wrongfully occupied by the Japanese. Further, in the 14th-15th centuries, the island had become a major center of pirate activity. On 1419/6/9, Taejong, former King of Korea, and/or his successor King Sejong, declared war on Tsushima. Ten days later, on 6/19, a fleet of Korean warships set sail for Tsushima under the command of Yi Jong-mu. The fleet, consisting of some 17,000 men on 227 ships, arrived at the island the following day.

Japanese forces performed a successful ambush against their Korean counterparts on 6/26, in what is known as the Battle of Nukadake. A cease-fire was called on 7/3, and the Korean fleet withdrew for a time. However, fighting eventually resumed, and ended in the head of the Sô clan surrendering to the Korean forces on 9/29.

Gallery labels at the "Story of King Sejong" museum in Seoul represent these events as the successful "subjugation" of Daemado; however, the invasion did not result in any notable political changes. The samurai Sô clan remained in control of the island, and remained subordinate or deferential to the Joseon court, as they already had been in the past. Though the Sô regularly dispatched envoys to pay respects and tributary gifts to the Joseon court, and otherwise acted the role of a Korean vassal well into the 19th century, the island never came under Korean control and remains part of Japan today.

In the 1440s, Joseon and the Sô reached an agreement to help curb the pirate problem; the Sô would take on the responsibility of cracking down on smuggling and pirate activity, and enforcing a system of trading licenses, in exchange for stipends and trading rights for themselves.

References

• Gallery labels, Story of King Sejong Museum, Seoul.[1]