Who was Admiral Yi Sun-sin?
Yi Sun-sin (1545 to 1598) was the Korean admiral who led the navy of Joseon against the Japanese invasions ordered by Toyotomi Hideyoshi. His victories at sea cut the invaders off from supplies, yet his own court arrested him in 1597. Reinstated after a disaster, he won at Myeongnyang and was killed by a bullet at Noryang in December 1598.1
For seven years one man stood between the Japanese invasion fleets and the western coast of Korea. Yi Sun-sin won battle after battle at sea, was arrested and stripped of his rank by his own court, came back to rebuild a navy that had almost ceased to exist, and fell in the last great sea battle of the war. Korea honors him as a national hero, and Japanese reference works give him a plain, respectful entry.2
A slow start in Seoul and on the frontier
Yi was born in 1545 in Seoul, the Joseon capital, and the Encyclopedia of Korean Culture places his birth in Geoncheon-dong, near today's Inhyeon-dong in central Seoul. Korea marks his birthday on 28 April, as the Maeil Shinmun notes. According to the National Institute of Korean History, he fell from his horse during a military examination in 1572 and was disqualified. He passed in 1576, though only in the third grade, as the Encyclopedia of Korean Culture notes.3
Several of his early posts were small forts on the northern frontier in Hamgyong province, facing raids by Jurchen bands. After a raid on the frontier island of Nokdundo, some time after 1586, he was blamed, punished and sent to serve without rank; the National Institute of Korean History adds that he had asked for reinforcements and been refused. Britannica sums it up: he was twice discharged after false accusations by jealous colleagues.4
Left Navy Commander of Jeolla, 1591
In 1591 Yi was named commander of the Left Navy of Jeolla province, on the south-western coast. The promotion skipped several ranks and drew objections at court; it came on the recommendation of the minister Yu Seong-ryong. Yi used the year he had well. He drilled his crews, stocked weapons and supplies, and built turtle ships, so that his squadron, unlike much of the Korean army, was ready when the invasion came.5
The turtle ship: fact and legend
Yi did not invent the turtle ship (geobukseon). The Annals of the Joseon Dynasty mention one fighting a mock Japanese vessel in 1413. Yi revived the design as a fighting ship. Planks laid over the deck of a standard Korean warship formed a shell, with knives and awls set in rows across the top to impale boarders. A dragon head at the bow served as a gunport, and cannon fired from the stern and both sides. The turtle ship first fought in Yi's second sortie of 1592, at Sacheon.6
Was it iron-clad? Britannica writes that it is thought to have been the first ironclad battleship in history, with armored plates over the upper deck. The Encyclopedia of Korean Culture says the ironclad claim lacks solid evidence: the spikes are documented, armor is not. Writing in the Weekly Kyunghyang, Lee Ki-hwan points out that Yi's own 1592 report mentions iron spikes on the back of the ship but no iron plating, and traces the ironclad image largely to Western writers of around 1900.7
No turtle ship survives, and there are no contemporary building plans. The best-known drawings come from the Yi Chungmugong jeonseo, the collected works of Yi compiled by royal order in 1795, some two centuries after the war, and its two turtle ships differ from each other.8
The campaign of 1592
The invasion ordered by Toyotomi Hideyoshi began in the spring of 1592. Japan calls these wars the Bunroku and Keicho campaigns. At sea the story was different. 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. By Britannica's account, these victories cut the Japanese armies off from supplies and reinforcements.9
Commander of the Three Provinces
In 1593 Yi was given command of the navies of all three southern provinces, as Naval Commander of the Three Provinces (Samdo sugun tongjesa), with his headquarters on Hansan Island. Long peace negotiations followed, and through those years the navy 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, rivals led by Won Gyun accused him, and he was removed and taken to Seoul.11
The National Institute of Korean History describes a harsh interrogation that put his life in danger, says a plea by the minister Jeong Tak saved him, and notes that some contemporaries saw the affair as a Japanese counter-intrigue. He was stripped of his rank and sent to serve as a common soldier, while Won Gyun took over the fleet.12
Chilcheollyang and Myeongnyang
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 turned back to Yi. He found only twelve warships and about 120 men.13
With that remnant he blocked the narrow Myeongnyang strait on the sixteenth day of the ninth lunar month of 1597. Korean records say his thirteen ships (twelve in one record) faced 133 Japanese warships and destroyed 31. These figures come from the Korean side only. In Britannica's summary, Yi went on from there to restore Korea's control of the seas.14
Noryang and the last words
Hideyoshi died in 1598 and the Japanese prepared to leave Korea. Konishi Yukinaga was hemmed in at Suncheon, and Shimazu Yoshihiro sailed to break him out. Yi now fought alongside the Ming admiral Chen Lin who, by Korean accounts, was at first inclined to let the Japanese go until Yi persuaded him to fight.15
The battle in the Noryang strait began in the night and ran into 16 December 1598, the nineteenth day of the eleventh lunar month. A stray bullet killed him. Korean records give his last order as a plea not to announce his death while the battle was at its height. The line goes back to Yu Seong-ryong's war memoir, the Jingbirok, and its exact wording is uncertain. The National Institute of Korean History adds that his nephew Yi Wan hid the death and kept the fleet fighting.16
How he fought
- Preparation first. His squadron was trained and supplied before the first Japanese ship arrived.17
- Guns, not boarding. Covered ships and cannon denied the Japanese their favorite tactic of grappling and boarding.18
- Working with allies. In 1598 he brought Chen Lin's Ming squadron into the final battle.19
Undefeated in 23 battles?
The Encyclopedia of Korean Culture credits him with a record of unbroken victories in many battles. Korean popular writing gives it a number, 23 battles and 23 victories, as in a 2011 opinion piece in the Maeil Shinmun. The total depends on how the fighting is counted: one sortie in 1592 could include several fights on consecutive days, and none of the reference works used here gives a fixed official list. The safe reading is that Yi never lost a battle he commanded; the exact figure of 23 is a tradition, not a settled tally.20
The Japanese view
Japanese reference works treat Yi without caricature. The entries on Kotobank, among them one by Kasuya Ken'ichi in the Nipponica encyclopedia, describe his victories, the false 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.21
A story repeated in Korea says that Togo Heihachiro, victor of the Battle of Tsushima in 1905, refused to be compared with Yi and called him the only true god of war. The 2011 Maeil Shinmun piece repeats it only as something that is said. No contemporary Japanese record of the remark appears in the sources used here, so the quote should be treated as unverified. The comparison with Horatio Nelson, by contrast, is on record: the British admiral and naval historian G. A. Ballard drew it, as the Encyclopedia of Korean Culture notes.22
The war diary
Yi kept a diary through the war, the Nanjung Ilgi. According to UNESCO 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 2013.23
Honors and memory today
After his death, in 1604 he was enrolled as a merit subject of the first class, and in 1793 raised to the rank of chief state councilor. His posthumous name, Chungmu, gives him the title by which Koreans know him, Chungmugong. The Hyeonchungsa shrine in Asan received a royal name plaque in 1707.24
The bronze statue at Gwanghwamun in Seoul was unveiled on 27 April 1968, according to the Seoul Shinmun, as part of a 1966 to 1972 program of statues of national heroes that the newspaper ran with government funding. Kim Han-min's film trilogy, The Admiral: Roaring Currents (2014), Hansan: Rising Dragon (2022) and Noryang: Deadly Sea (2023), reached a huge audience; the first film drew about 17.6 million viewers, a Korean record, as the Weekly Kyunghyang reports.25
