Last month I wrote a post which listed some of history’s undefeated generals. An acquaintance of mine pointed out on Facebook that I failed to list the Korean general Yi Soon-sin. I know that Yi Soon-sin, with his powerful turtle-ships and against nigh impossible odds, drove the Japanese out of Korea in the 1590s. However, I did not know that he was undefeated. Considering how remarkable his exploits were, it is only fair that I rectify my omission by a post dedicated solely to him. Today is also the anniversary of my blog – three years! Considering that this post involves the samurai (as antagonists, but still), that my blog is called The Saviour’s Samurai, and that the Japanese invasion of Korea, in which Yi Soon-sin proved his might, began in May 1592, this post is amazingly fitting.

First, a bit of backdrop. It is the 1590s CE. Korea is about 200 years into the Joseon Dynasty, and it though flourishes culturally, its governance has been weakened by continuing violent power struggles between political factions and associated purges of political opponents. Militarily, it faces continuous raids by the Jurchens to the north. Ming China, the successor state to the Mongolian Yuan Dynasty, was once mighty but now struggles amidst political turmoil, economic trouble, Jurchen raids, and colonial expansion by the Portuguese, Spanish, and Dutch Empires. Japan, after over a century of constant bickering, feuding and war between dozens upon dozens of warlords (daimyo), has been recently united by Toyotomi Hideyoshi, who continued the conquests begun by his former master Oda Nobunaga. However, this newly unified Japan is fragile, as the daimyo and samurai grow restless. Also, like China, Japan is under pressure from European colonial expansion. Japan is superior in land combat, with its samurai highly trained both in the traditional arts of bow and sword arts and the strategies of recently-introduced gunpowder weapons. China and Korea, on the other hand, outclass the Japanese in naval warfare, with ships possessing both a superior range of fire and large amounts of on-board cannons.

Now, to the conflict: To keep his warlords and generals occupied, and to challenge the growing European economic influence over the Japanese islands, Hideyoshi prepares to strike both Korea and China with the might of his samurai warriors and iron-plated ships. Korea does not stand a chance. The initial Japanese landing parties slip past the naval defenses, and quickly establish a beachhead. Korean ships are sunk and soldiers cut down. The Koreans face crushing defeat after crushing defeat, and nearly the entire peninsula is overrun by Japanese forces. However, small pockets of resistance fight on. The leader of one of these small resistance units is Yi Soon-sin.

Yi was born April 28, 1545, and soon proved to be a bright and promising military student. After passing examination, he was posted along the Korean border, where he battled against Jurchen raiders. Meeting success after success on the battle-field, he attracted jealousy from some of his fellow commanders, and was discharged from the army. However, he managed to regain his position, and in the years preceding the Japanese invasion, Yi rapidly advanced through the military ranks. Ultimately, in 1591 he assumed command of the Left Jeolla Naval District. In his post, he oversaw the creation of turtle-ships (Geobukseon), with their numerous cannons and iron-spiked roofs, and introduced naval reforms. The following year, Hideyoshi attacked. As mentioned above, his armies rapidly smashed through the Korean defenses. But, his army need to be supplied and reinforced. And that is where Yi comes in.

Yi, despite never being trained in naval warfare, deploys his multi-decked, cannon-laden warships in innovative new formations, such as the V-shaped “crane wing,” inflicting devastating losses on the Japanese. In May 1592, a few days after Hideyoshi captured the city of Pusan, Yi attacks some 800 Japanese warships, setting 26 ablaze and scattering the rest. During that month and the next, Yi destroys 72 more enemy warships.  In July, he inflicts a decisive defeat against the Japanese at Hansan Island, destroying upwards of 66 ships out of 73 while incurring no losses of ships himself and hardly any casualties. In September, he attacks a flotilla of 800 with a fleet of only 180, and, through clever use of fire-ships, destroys some 400 ships. On land, Korean militias continued to harass the Japanese in guerilla warfare, and, with Yi’s smashing naval victories, the Korean army, now aided by the Ming, start to retake the peninsula. Hideyoshi’s goal to conquer Ming China fails, and in 1593 the Japanese withdraw.

But Hideyoshi is far from beaten. He plans to invade again, but first he must get rid of Commander Yi. He sends Japanese to the Korean command, where the soldier claims that he is a double agent willing to spy on Japan for Korea. Once in a position of trust, he reports that a large Japanese fleet is approaching, and suggests that the fleet may be destroyed at a particular location. King Seonjo, desperate to drive the remaining Japanese forces out of Korea, orders Yi to meet the Japanese at the specified location. Yi refuses, knowing that the area is shallow, with sharp rocks that could sink his fleet. He refuses and is stripped of his post, beaten, and tortured. The king wants him executed, but many of the officers protest, defending Yi based on his unblemished military record. The king relents and elects merely to reduce Yi’s rank to that of common soldier. With Yi disposed of, Hideyoshi once again invades Korea, in the year 1597. This time, the Ming send thousands of troops into Korea, helping the Korean forces halt the Japanese advance. On the seas, however, Korea meets with disaster. Yi’s successor, Won Gyun, attempts to intercept the Japanese navy. The Japanese ambush his fleet at Chilcheollyang, where Gyun’s 169 ships encounter 500 to 1,000 Japanese ships. The battle is a total disaster for Korea; the fleet that Yi worked so hard to build and develop is almost completely annihilated, with only 13 of the 169 ships managing to escape. Won and fellow commander Yi Eok-gi escape the scene only to be killed by Japanese soldiers when they get ashore.

Stunned at this loss, King Seonjo restores Yi to his position, but urges him to join the army on land since the Korean fleet is destroyed. Yi, however, insists on returning to naval command. He is left with the 13 surviving ships, and only 200 of his original 30,000 highly trained sailors. The Japanese, confident in victory, send out a fleet of 133 warships, plus over 200 additional support ships, to meet Yi. Yi, with expert knowledge of the seas, lures the fleet into the Myeongnyang Strait. Here, strong currents would force the Japanese to send in ships one at a time, and the narrow strait would prevent the Japanese from attempting flanking maneuvers. Also, the surrounding hillsides cast shadows over the water in which the Korean ships can hide, and also allow land-based archers and cannon to support the fleet. Yi also stretches iron chains across the water to further constrict Japanese movement. Finally, on that particular day, a thick fog allows the Korean ships to hide from the Japanese. The resulting conflict is a decisive rout for the Japanese. 31 ships are lost, while the Koreans lose not a single ship and sustain less than twenty casualties.

Shocked at this turn of events, the Japanese try once more, the Battle of Noryang. This time, the Joseon fleet numbers 83 ships, which are joined by 63 Ming warships. In total, the joint Joseon-Ming forces controls about 150 ships, facing off against about 500 Japanese ships. Once again, Yi leads his navy to victory – about 200 Japanese ships are sunk, another 100 captured, and the Koreans and Ming lose not a single ship. Sadly, Yi himself does not survive the battle – in pursuit of the fleeing enemy ships, a stray shot from an arquebus (an early model of long-barreled gun) struck him down. Knowing that his wound was fatal, he declared “The war is at its height — wear my armor and beat my war drums. Do not announce my death.” And he died. Following this rout, Hideyoshi was forced into a stalemate. Realizing that his invasions had failed, he struck an agreement with Korea and withdrew his remaining troops.

And thus, though he did not live to see the end result, one man, Yi Soon-sin, saved Korea from Japanese invasion, fighting against seemingly insurmountable odds without ever suffering defeat.


  • William Weir, 50 Military Leaders Who Changed the World
  • Roger Tennant, History of Korea
  • Iain Dickie, Fighting Techniques of Naval Warfare: Strategy, Weapons, Commanders, and Ships: 1190 BC – Present
  • R. Barry Harmon, 5,000 Years of Korean Martial Arts: The Heritage of the Hermit Kingdom Warriors
  • Daniel Filliettaz-Domingues, “Yi Soon-shin: Battle of Hansan Island”
  • “Yi Sun-shin,” Encyclopedia Britannica
  • “Joseon,” Wikipedia
  • “Ming dynasty,” Wikipedia
  • “Japanese invasions of Korea (1592-98),” Wikipedia
  • “Battle of Myeongnyang,” Wikipedia
  • “Battle of Noryang,” Wikipedia
  • “Yi Sun-sin,” Wikipedia