Battles & Wars › Gunpowder empires › Imjin War (Japanese invasions of Korea)
Admiral Yi Sun-sin
1545–1598· Person· Asia & Pacific
Well documentedSolid records, physical evidence or scientific consensus.
Korea's most celebrated admiral, whose victories at sea helped defeat Japan's invasions of 1592–1598.
See it on the Battles & Wars map →What happened
Yi Sun-sin (이순신) passed the military exam at 31 and served on the northern frontier. Made a naval commander in 1591, he drilled his crews and built turtle ships (geobukseon), roofed warships bristling with cannon. In 1592 he won a string of battles that cut Japanese supply lines. Jailed and demoted in 1597 after court intrigue, he was restored once the fleet was lost and won at Myeongnyang with 13 ships. He was killed at Noryang in 1598.
Why it matters
His victories protected Korea's southwest and its sea lanes, helping save the Joseon kingdom; he is Korea's foremost national hero.
Legacy and how we know
His own war diary, Nanjung Ilgi (on UNESCO's Memory of the World register), his reports to the throne, and the Joseon Annals. His statue stands in Seoul's Gwanghwamun Square.
Still debated
What turtle ships looked like, and whether they were iron-plated, is uncertain; the claim that he never lost a battle depends on how battles are counted.
Inside this (3)
Connections (3)
▸Admiral Yi Sun-sin won Battle of Hansan IslandWell documented
The connection
Hansan showed Yi's method. Judging the Gyeonnaeryang strait, where Wakisaka Yasuharu's fleet lay, too narrow and rocky for his heavy panokseon warships, he lured the enemy into open water. There he kept his distance and let Korean cannon do the work, denying the Japanese, who relied on boarding, a chance to fight hand to hand.
When and how
Waters between Geoje and Hansan islands, off Tongyeong, August 14, 1592; Yi with fellow commanders Yi Eok-gi and Won Gyun.
How we know
Yi's own battle report to King Seonjo and his war diary describe the plan, and Japanese records of the Wakisaka family confirm the defeat.
Debates and open questions
How far the crane's wing was Yi's own idea rather than an existing formation adapted to the sea is unclear, and details rely mostly on Korean sources.
▸Admiral Yi Sun-sin saved Korea at sea in Imjin War (Japanese invasions of Korea)Well documented
The connection
In 1592 Yi won every major sea battle, including Okpo, Sacheon, Hansan and Busan, keeping Jeolla Province and its rice harvest out of Japanese hands. In 1597, after his jailing and demotion, he was restored and won at Myeongnyang. He was killed at Noryang in December 1598, in the war's last great battle, as the Japanese withdrew.
When and how
Korea's southern seas, 1592–1598; Yi as Left Naval Commander of Jeolla Province, then supreme naval commander of the three southern provinces.
How we know
Yi's war diary, Nanjung Ilgi, now on UNESCO's Memory of the World register, his reports to the court, and the Annals of the Joseon Dynasty.
Debates and open questions
How decisive the navy was compared with Ming armies and Korean guerrillas is debated, and 'never lost a battle' depends on what counts as one.
▸Admiral Yi Sun-sin won, with just 13 ships, the Battle of MyeongnyangWell documented
The connection
Restored to command after the Korean fleet was destroyed at Chilcheollyang, Yi had only about 13 ships. He chose the Myeongnyang Strait, a narrow channel with some of Korea's strongest tidal currents, where numbers counted for little. His flagship held the narrows almost alone at first; when the tide turned, Japanese ships fell into confusion and around 30 were destroyed.
When and how
Myeongnyang Strait (Uldolmok), between Jindo Island and the mainland, October 26, 1597; Yi against a Japanese fleet including Tōdō Takatora and Kurushima Michifusa, who was killed.
How we know
Yi's war diary describes the battle, his report to the king before it said 'I still have 12 ships', and Japanese records confirm the defeat.
Debates and open questions
Japanese fleet size (estimates from about 130 to over 300 ships) is disputed, and the story of iron chains strung across the strait is unconfirmed.