History of
Admiral Yi Sun-sin

1545 – Admiral i Sun-sin was born on April 28 in Hanseong (modern-day Seoul), during the reign of King Injong of the Joseon Dynasty. He was born into the prestigious Deoksu Yi clan, though his family faced political and financial hardships due to factional purges.

1550s–1560s – Yi received a traditional Confucian education, excelling in both literary and martial disciplines. From a young age, he demonstrated strong moral character, resilience, and a sense of duty. His early training included archery, horseback riding, and classical studies.

1576 – After an initial failure due to an accident during the cavalry test, Yi passed the Military Service Examination (무과; mukwa) at the age of 32, a relatively late age for the time. He was appointed to minor frontier posts, where he distinguished himself through diligence and incorruptibility.

1583 – Yi successfully led a campaign against the Jurchen tribes on the northern border. His strategic mind and firm discipline earned him the attention of higher officials, but political rivalries, particularly with the powerful admiral Won Gyun, would later impact his career.

1591 – Amid rising tensions with Japan under Toyotomi Hideyoshi, Yi was appointed Commander of the Left Jeolla Naval Station (전라좌수사). Sensing the imminence of war, Yi reorganized the naval forces, trained his men rigorously, improved fortifications, and revived the production of the Geobukseon (거북선; Turtle Ship)—an innovative, iron-clad warship designed to break enemy formations.

1592 – The Japanese invasion of Korea—known as the Imjin War—began in April. Yi quickly established naval superiority with a series of decisive victories, beginning with the Battle of Okpo, followed by triumphs at Sacheon, Dangpo, and Hansando.

Yi’s control of the southern coast effectively severed Japanese supply lines and stalled their advance into the Korean peninsula.

1593–1596 – Yi maintained naval dominance while refining his tactics. He emphasized speed, precision, and psychological warfare. His fleets conducted preemptive strikes, ambushes, and nighttime operations that demoralized the Japanese navy.

1597 – Court politics, driven by jealousy and intrigue, led to Yi’s dismissal and imprisonment on false charges. His rival, Won Gyun, was appointed in his place. The result was catastrophic—Won Gyun lost most of the fleet in the Battle of Chilcheollyang.

Yi was reinstated, now commanding only 13 warships.

1597 – Battle of Myeongnyang

In one of the most astonishing naval feats in history, Yi used the narrow currents of the Myeongnyang Strait to ambush a Japanese fleet of over 300 ships. Despite being outnumbered more than 20 to 1, he achieved a resounding victory, restoring Korean naval strength.

1598 – Final Campaign and Death

Yi continued to disrupt Japanese operations in coordination with Ming Chinese forces. On December 16, 1598, during the Battle of Noryang, Yi was fatally shot by a stray bullet. Knowing the morale of his troops could collapse, he ordered that his death be kept secret until the battle was won. His final words were:

“The war is at its height. Do not announce my death.”

Admiral Yi Sun-sin is widely regarded as one of the greatest naval commanders in world history. He fought over 20 major naval battles without a single defeat and played a decisive role in defending Korea from foreign conquest.

His meticulous war diaries, the Nanjung Ilgi (난중일기), are designated as a national treasure and UNESCO Memory of the World, offering rare insight into the mindset of a brilliant, self-reflective leader.

His legacy transcends military genius—it is one of unwavering integrity, loyalty to the people, and a deep sense of service to the nation. Monuments, naval academies, and annual commemorations throughout Korea and abroad continue to honor his contributions.