Who was Admiral Yi Sun-sin?
Yi Sun-sin (1545 to 1598) was the Korean admiral who commanded the Joseon navy against Toyotomi Hideyoshi's invasions of 1592 to 1598. His victories at sea cut the Japanese armies off from supplies. Arrested by his own court in 1597, he was reinstated after a naval disaster, won at Myeongnyang and was killed at Noryang on 16 December 1598.1
Yi Sun-sin commanded in the sea battles that decided the naval war of 1592 to 1598. In his first year of war he won a run of fights along the southern coast, among them the victory off Hansan Island. Five years later, with the navy almost wiped out, he held the Myeongnyang strait with 13 ships, and in December 1598 he was killed in the Battle of Noryang, the last great sea battle of the war. Korea honors him as a national hero.2
Early life: a slow start in Seoul and on the frontier
Yi was born in Seoul in 1545; Korea marks his birthday on 28 April. In 1572 he fell from his horse during the military examination and failed. He passed it in 1576.3
His early posts included small forts on the northern frontier in Hamgyong province, facing raids by Jurchen bands. On the frontier island of Nokdundo he asked for more troops and was refused; after a Jurchen raid the court blamed him alone, and he was sent to serve without rank, the first of two such punishments in his career.4
Left Navy Commander of Jeolla, 1591
In 1591 Yi became commander of the Left Navy of Jeolla province, on the southwestern coast. The jump in rank drew objections at court. Yu Seong-ryong, the minister who later wrote a memoir of the war, had recommended him. Yi used the year before the invasion to drill his crews, stock weapons and supplies and build turtle ships, and his diary records a test firing of the turtle ship's guns shortly before the Japanese landed.5
Did Yi Sun-sin invent the turtle ship?
No. The Annals of the Joseon Dynasty mention a turtle ship (geobukseon) in 1413, when King Taejong watched one in a mock fight against Japanese ships. Yi revived the design as a fighting ship. Planks laid over the deck of a standard Korean warship formed a shell, knives and awls set in rows across the top stopped boarders, a dragon head at the bow held a gunport, and guns fired from both sides and the stern. The turtle ship first fought at Sacheon in 1592.6
Was it iron-clad? Britannica calls it possibly the first ironclad battleship, with armored plates over the upper deck. The Encyclopedia of Korean Culture says the iron-plating claim rests on oral tradition and Japanese sources of doubtful reliability and remains unconfirmed. Writing in the Weekly Kyunghyang, Lee Ki-hwan notes that Yi's own 1592 report mentions iron spikes on the ship's back but no iron plates.7
No turtle ship survives, and there are no contemporary building plans. The best-known drawings come from the Yi Chungmugong jeonseo, Yi's collected works compiled by order of King Jeongjo in 1795, some two centuries after the war, and its two turtle ships differ from each other.8
Yi Sun-sin's greatest victories: the campaign of 1592
The invasion ordered by Toyotomi Hideyoshi began in the spring of 1592; Japan calls the two invasions the Bunroku and Keicho campaigns. Yi won his first battle at Okpo on the seventh day of the fifth lunar month, then fought at Sacheon and Dangpo, defeated a large Japanese fleet off Hansan Island in the summer, and attacked the main Japanese base at Busan on the first day of the ninth lunar month. These victories cut the Japanese armies off from supplies and reinforcements by sea.9
Commander of the Three Provinces
In 1593 Yi was named Naval Commander of the Three Provinces (Samdo sugun tongjesa), in charge of the navies of all three southern provinces, with his headquarters on Hansan Island. Long peace negotiations followed, and through those years his fleet guarded the south coast.10
Why was Yi Sun-sin arrested in 1597?
Yi was arrested in early 1597 over a tip, passed on by a Japanese double agent called Yoshira, that the general Kato Kiyomasa would cross from Japan at a given time. Ordered to intercept him, Yi suspected a trap and hesitated, and Kato landed unopposed. The court blamed Yi for disobedience, Won Gyun accused him, and he was removed and taken to Seoul.11
He was harshly interrogated and came close to execution. A plea by the minister Jeong Tak saved him, and he was sent to serve without rank under the general Gwon Yul, the second time he was so punished, while Won Gyun took over the fleet.12
How did Yi win at Myeongnyang with 13 ships?
The Japanese invaded again in 1597. In the seventh lunar month Won Gyun's fleet was caught at Chilcheollyang, near Geoje Island, and almost completely destroyed. The court reinstated Yi, who found 12 warships and about 120 men left.13
With 13 warships he blocked the narrow Myeongnyang strait on the sixteenth day of the ninth lunar month of 1597. By the Korean records, the Japanese fleet numbered 133 warships and lost 31 of them before it withdrew. These are Korean figures. Yi fought in the narrow channel, and when the strong tidal current turned, it worked against the larger Japanese fleet.14
How did Yi Sun-sin die?
Hideyoshi died in 1598 and the Japanese prepared to leave Korea. Konishi Yukinaga was cut off at Suncheon, and Shimazu Yoshihiro sailed to break him out. Yi now fought alongside the Ming admiral Chen Lin. Korean accounts say Konishi tried to buy Chen Lin off and that the Ming admiral was reluctant to fight until Yi persuaded him.15
The battle in the Noryang strait began in the night and ran into the morning of 16 December 1598, the nineteenth day of the eleventh lunar month. As Yi pursued the retreating Japanese ships, a stray bullet struck him and he died on deck. The Annals of the Joseon Dynasty record his death by gunfire; a historian's comment there says an officer, Yi Mun-uk, covered the body and kept the drums beating so that the crews fought on, while other Korean accounts give that role to Yi's nephew Yi Wan.16
His last words come from later accounts. Korean reference works give them as an order: “The battle is at its height. Do not announce my death.” The report of the battle in the Annals records no last words.17
How he fought
- Preparation first. His squadron was trained and supplied before the first Japanese ship arrived.18
- Guns, not boarding. Covered ships and cannon denied the Japanese their favorite tactic of grappling and boarding.19
- Working with allies. In 1598 his fleet fought the final battle together with Chen Lin's Ming squadron.20
Did Yi Sun-sin ever lose a battle?
No battle Yi commanded is recorded as a defeat. The great Korean naval disaster of the war, Chilcheollyang in 1597, came while he was under arrest and Won Gyun held the command. The British admiral G. A. Ballard, writing in 1921, called him a commander “who never knew defeat and died in the presence of the enemy.”21
Korean popular writing often puts a number on the record, 23 battles and 23 victories, as in a 2011 opinion piece in the Maeil Shinmun. Neither the Encyclopedia of Korean Culture nor the National Institute of Korean History gives such a count, and the total depends on how separate fights within one sortie are counted, so the figure 23 is a tradition, not a settled tally.22
What did the Japanese think of Yi Sun-sin?
Japanese reference works treat Yi without caricature. The entries collected on Kotobank, among them Kasuya Ken'ichi's in the Nipponica encyclopedia, describe his victories, the accusations that cost him his command, his return and his death at Noryang. His opponents were capable soldiers: in 1598 Konishi Yukinaga held out at Suncheon until the withdrawal, and Shimazu Yoshihiro risked his fleet to relieve him. The wider world of the samurai generals is covered in the greatest commanders of feudal Japan.23
Ballard also compared him with Horatio Nelson: “It is always difficult for Englishmen to admit that Nelson ever had an equal in his profession, but if any man is entitled to be so regarded, it should surely be” Yi.24
The war diary
Yi kept a diary through the war, the Nanjung Ilgi. It runs from January 1592 to November 1598, survives in seven volumes, and records battles, weather, terrain, his own moods and the lives of ordinary people. UNESCO added it to the Memory of the World register in 2013. An English translation by Ha Tae-hung was published in 1977.25
How is Yi Sun-sin remembered today?
In 1604 he was enrolled posthumously as a merit subject of the first class, and in 1793 he was raised to the rank of chief state councilor. His posthumous name, Chungmu, gives the title by which Koreans know him, Chungmugong. He is buried at Eorasan in Eumbong-myeon, Asan, and the Hyeonchungsa shrine in Asan received a royal name plaque in 1707.26
The bronze statue at Gwanghwamun in Seoul, by the sculptor Kim Se-jung, was unveiled on 27 April 1968. Kim Han-min's film trilogy, The Admiral: Roaring Currents (2014), Hansan: Rising Dragon (2022) and Noryang: Deadly Sea (2023), retold his three best-known battles; the first film drew about 17.6 million viewers, at the time the largest audience of any film in South Korea.27
