Yi Sun-sin

Yi Sun-sin was born on 28 April 1545 in Hanseong (Seoul), in the Geoncheon-dong district, the son of Yi Jeong. According to a later biography the family moved to Asan before his eighth year, where the family of his future wife lived. His family offered little support for a career; he depended on patrons such as the scholar-official Yu Seong-ryong.

In 1576 he passed the military state examination and received posts in, among other places, the northern border region. His career saw setbacks, including dismissal and imprisonment. In 1591 the government, with the support of Yu Seong-ryong, appointed him commander of the Left Jeolla fleet, with headquarters at Yeosu.

As commander of the Left Jeolla fleet he strengthened the navy with reforms, including the construction of a geobukseon (turtle ship). When Japan invaded Korea in 1592 he fought, together with other Joseon fleet commanders, at Okpo, Sacheon and Hansando, among other places. His fleet consisted largely of panokseon, heavily armed Korean warships.

The geobukseon was a covered warship with cannon, a dragon head on the bow and a deck fitted with iron spikes against boarding. Earlier ships of this type (gwiseon) are already mentioned in the Joseon annals in 1413 and 1415; the ship first appeared in combat at Sacheon in 1592. Whether the deck was clad in iron is disputed: Korean sources from his time do not mention it.

At Hansando (August 1592) he lured Japanese ships into open water and enclosed them with his own vessels in a U-shaped 'crane wing' formation. At Myeongnyang (October 1597) he used the strong currents of the narrow strait. The numbers of ships and losses vary between sources.

Joseon Korea was a Confucian state with a bureaucracy of scholar-officials, in which civil officials ranked above military officers and court factions competed over appointments. The country stood in a tributary relationship to Ming China. After Toyotomi Hideyoshi had reunified Japan, he prepared an invasion of Korea, with China as the ultimate goal.

In 1592 Japanese armies landed at Busan and reached Hanseong within a few weeks. Ming China sent troops to support Korea and Korean volunteer militias also resisted. A second invasion followed in 1597. The war caused great destruction, massacres and forced deportations, and ended in 1598 with the Japanese withdrawal after Hideyoshi's death.

Yi's victories limited Japan's ability to supply and reinforce its armies by sea, and thereby influenced the course of the war on land. How heavily his share weighs alongside that of Ming troops, Korean militias, supply problems and Hideyoshi's death is assessed differently by historians.

In 1597 he was arrested and tortured after accusations against him; he escaped the death penalty and had to serve as a common soldier under General Gwon Yul. His successor Won Gyun lost the fleet at Chilcheollyang, after which Yi was given command again. Historians discuss the role of political factions and the relationship between Yi and Won Gyun.

On 16 December 1598 (Gregorian date) Yi was killed during the naval battle of Noryang, struck by a stray bullet from a Japanese musket, as the Japanese armies were withdrawing from Korea. He was buried at Asan, next to his father. Posthumously he received the honorific title Chungmu (Lord of Loyal Valor).

His war diary, the Nanjung Ilgi, is part of UNESCO's Memory of the World Register and is an important source on the war. In Korea he is commemorated as a symbol of resistance to the invasion. Historians distinguish his documented deeds from later image-making, including about the turtle ship, whose armouring is disputed.