In 1576, Yi passed the
military examination (). He is said to have impressed the judges with his archery, but failed to pass the test when he broke a leg during the
cavalry section. After he re-entered and passed the examination, he was posted to the
Bukbyeong (Northern Frontier Army) military district in
Hamgyeong province. However, he was the oldest junior officer at the age of thirty-two. There, Yi experienced battles defending the border settlements against the
Jurchen marauders and quickly became known for his strategic skills and leadership. In 1583, he lured the Jurchen into battle, defeated the marauders, and captured their chief,
Mu Pai Nai. According to a contemporary tradition, Yi then spent three years out of the army upon hearing of his father's death. After his return to the front line, Yi led a string of successful campaigns against the Jurchen. However, his brilliance and accomplishments so soon in his career made his superiors jealous, and they falsely accused him of
desertion during battle. The conspiracy was led by General
Yi Il, who would later fail to repel the Japanese invasion at the
Battle of Sangju. This tendency to sabotage and frame professional adversaries was very common in the later years of the Joseon military and government. Yi was stripped of his rank, imprisoned, and tortured. After his release, Yi was allowed to fight as an enlisted soldier. After a short period of time, however, he was appointed as the commander of the Seoul
Hunryeonwon (a military training center) and was later transferred to a small county, to be its military
magistrate. Yi's efforts in northern Korea were rewarded when he was assigned as Commander of the
Jeolla Province () Left Naval District. Within the span of a few months in late 1590, he received four military appointments, in rapid succession, with each subsequent post carrying greater responsibility than the last: Commander of the Kosarijin Garrison in
Pyongan Province, Commander of the Manpo Garrison, also in
Pyongan Province, and the Commander of the
Wando Garrison, in
Jeolla province, before finally receiving the appointment as Commander of the Left Jeolla Naval District. The royal court was in a state of confusion over the possibility of a war with Japan, now unified under the rule of
Toyotomi Hideyoshi, and the unstable situation in
Manchuria where a young Jurchen chieftain named
Nurhaci was gathering strength.
Nurhaci's descendants would become masters of China as founders of the
Qing dynasty in a few decades, after invading Korea in
1627 and
1637. Yi assumed his new post at
Yeosu on the 13th day of the 2nd lunar month of 1591 (March 13, 1591). From there, he was able to undertake a buildup of the regional navy, which was later used to confront the Japanese invasion force. He subsequently began to strengthen the province's navy with a series of reforms, including the construction of the
turtle ship.
Japanese invasions of Korea (1592–1598) Yi is remembered for his numerous victories fighting the Japanese during the
Japanese invasions of Korea (1592–1598), also referred to as the Imjin War. Among his twenty-three victories, the
Battle of Myeongnyang and the
Battle of Hansan Island are the most famous battles. In 1592,
Toyotomi Hideyoshi gave the order to invade Korea and use it as a forward base to conquer
Ming China. After the Japanese attacked
Busan, Yi began his naval operations from his headquarters at
Yeosu. Despite never having commanded a naval battle in his life, he won the
Battle of Okpo,
Battle of Sacheon, and several others in quick succession. His string of victories made the Japanese generals suddenly wary of the threat at sea. Yi never lost a battle during the Imjin War. The next day, the Jeolla fleet sailed to an arranged location where Admiral
Wŏn Kyun (원균; 元均; 1540–1597) was supposed to meet them, and met the admiral on June 15. The augmented flotilla of 91 ships then began circumnavigating the
Geoje Island, bound for the Gadeok Island, but scouting vessels detected 50 Japanese vessels at the harbor of Okpo. The Koreans spotted five more Japanese vessels that night, and managed to destroy four of them. Admirals Yi and Won sailed with a total of 26 ships (23 under Admiral Yi) toward the Bay of
Sacheon upon receiving an intelligence report of a Japanese presence. Admiral Yi had left behind his fishing vessels that used to make up most of his fleet in favor of his newly completed
turtle ship. However, the admirals arrived in Busan nine days before Hideyoshi's order was actually issued, and assembled a squadron to counter the Korean navy. under the commands of Admirals Yi Sun-sin and Yi Eok-gi was carrying out a search-and-destroy operation because the Japanese troops on land were advancing into
Jeolla Province. Several Korean prisoners of war were rescued during the fight. Admiral Wakisaka escaped due to the speed of his flagship. Each broadside featured six gun ports, each armed with a mortar, supplemented by additional mortars positioned ahead and astern. The dragon-like figurehead emitted sulfurous smoke and created a smokescreen to obscure the ship's movements. Narrow slits between the gun ports allowed for the discharge of fire-arrows and gunfire. The roof, covered with planks and spikes, thwarted Japanese boarding tactics.
Dismissal of Yi Sun-sin One day, he told General Kim Gyeong-seo that the Japanese general
Katō Kiyomasa would be coming on a certain date with a great fleet for another attack on the south shores and insisted that Admiral Yi be sent to lay an ambush. General Kim agreed and sent the message to Field Marshal
Gwon Yul (권율; 權慄; 1537–1599), Commander-in-Chief () of the Joseon military, who, in turn, sent the message to
King Seonjo.
King Seonjo, who was desperate for victories to loosen the Japanese grip on his kingdom, gave permission for the attack. When General Kim gave Admiral Yi his orders, the admiral refused to carry them out, for he knew that the location given was studded with sunken rocks and was thus extremely dangerous. Admiral Yi also refused because he did not trust the words. When General Kim informed the king of Admiral Yi's refusal, the admiral's enemies at court quickly insisted on his replacement by General
Wŏn Kyun, former commander of the Gyeongsang Province Western Fleet & Commander of the
Jeolla Province Ground Forces. They advised that Admiral Yi be arrested. As a result, in 1597, Yi was relieved of command, placed under arrest, and taken to Seoul in chains to be imprisoned and tortured. Yi was tortured almost to the point of death by using simple torture tactics such as whipping, flogging, burning, the cudgel, and torture by leg-breaking.
King Seonjo wanted to have Yi killed, but the admiral's supporters at court, chiefly the minister
Jeong Tak (정탁; 鄭琢; 1526–1605), convinced the king to spare him due to his past service record. The prime minister,
Yu Sŏngnyong, who was Yi's childhood friend and his main supporter, remained silent during this deadly hour. Spared the death penalty, Admiral Yi was again demoted to the rank of a common infantry soldier under General
Gwon Yul. This penalty was worse than death for Joseon generals at that time, since they lived by honor. However, Yi responded to this humiliation as a most obedient subject, quietly going about his work as if his rank and orders were appropriate. Despite his low rank, many officers treated him with respect, since they knew that the admiral did nothing wrong. Yi would stay under General Gwon Yul's command for a short while until Wŏn Kyun's death at the
Battle of Chilchonryang, which would lead to his reinstatement.
Joseon defeat at Chilchonryang and reinstatement of Admiral Yi With Yi stripped of influence and negotiations breaking down in 1596, Hideyoshi again ordered an attack on Joseon. The second Japanese invasion landed in the first month of 1597 with a force of 140,000 men transported on 1000 ships. In response, Ming China sent thousands of reinforcements to aid Joseon. With the help of the Ming, the Joseon army was able to halt the Japanese offensive and push it back during the winter of 1597, before the Japanese were able to reach the Joseon capitol of
Hanseong. On the high seas, Yi's successor
Wŏn Kyun failed to respond to reports from his scouts and allowed the Japanese to land critical reinforcements at
Sosang Harbor for their land offensive unopposed. Without adequate reconnaissance or planning, Wŏn Kyun decided to attack with the entire naval force of Joseon at his disposal – a fleet consisting of 150 warships operated by 30,000 men that had been carefully assembled and trained by Admiral Yi. Wŏn Kyun left anchor at
Yeosu with the fleet and sailed into waters marked by treacherous rocks. The Japanese ambushed the Joseon fleet in the
Battle of Chilchonryang on August 28, 1597. Ignorant of the strength and disposition of the enemy, Won was stunned to find a Japanese fleet of 500 to 1000 ships which immediately closed for melee combat, denying the Joseon ships the advantages of superior seamanship and cannon fire. The exhausted Joseon sailors were reduced to fighting boarding actions while heavily outnumbered and were slaughtered
en masse. The Joseon fleet was decimated with only 13 warships surviving under Admiral
Bae Seol, who fled before battle was fully engaged to save the warships under his command. After the destruction of the Joseon fleet, Wŏn Kyun and
Yi Eok-gi, another Joseon commander, fled to an island with a band of survivors but were killed by waiting Japanese soldiers from the nearby fort. When
King Seonjo and the royal court learned of the catastrophic defeat, they hurriedly pardoned and reinstated Admiral Yi as commander of the greatly reduced Joseon fleet.
Battle of Myeongnyang Admiral Yi located the 13 warships and rallied the 200 surviving sailors. Together with his flagship, Admiral Yi's entire fleet totaled 13 ships, none of which were turtle ships. In the belief that the Joseon fleet would never be restorable,
King Seonjo, sent an edict to Admiral Yi to abandon the warships and take his men to join the ground forces under General Gwon Yul. Admiral Yi responded with a letter written "
...your servant still doth have twelve warships under his command and he is still alive, that the enemy shall never be safe in the West Sea" (the
Yellow Sea being the closest body of water to
Hanseong). Emboldened after their victory at Chilchonryang, Japanese admirals
Kurushima Michifusa,
Todo Takatora,
Kato Yoshiaki, and
Wakisaka Yasuharu sailed out of Busan Harbor with a fleet of over 300 ships, confident that they would defeat Admiral Yi. Elimination of the Joseon fleet would mean unrestricted movement of supplies and reinforcements from Japan for the land offensive towards Hanseong and beyond. After careful study of potential battlefields, in October 1597 Admiral Yi lured the Japanese fleet into the
Myeongnyang Strait, by sending a fast warship near the Japanese naval base and luring the Japanese fleet out of anchorage. The Japanese assumed that this was a Joseon scouting ship and that pursuing it would lead to the location of Admiral Yi, giving them an opportunity to destroy the remnants of the Joseon fleet. What they did not know was that they were being lured into a masterfully devised trap. There were several reasons why Admiral Yi decided on this location for battle. Myeongnyang Strait had currents, eddies, and whirlpools so powerful that ships could only enter safely a few at a time. The north–south tidal flow reversed every three hours, limiting the time that the Japanese could mount an offensive. The strait was sufficiently narrow that it would prove impossible for the Japanese to flank or envelop the numerically inferior Joseon fleet. The deep shadows of the surrounding hillsides provided the Joseon ships with concealment. On that particular day there was also a heavy mist, dramatically reducing visibility in favor of the Joseon fleet. Therefore, despite being vastly outnumbered, Admiral Yi used the terrain restrictions to neutralize the Japanese navy's staggering numerical advantage. The Japanese fleet of approximately 333 ships (133 warships, at least 200 logistical support ships) entered Myeongnyang Strait in groups. The Japanese ships that made it through were met by 13 Joseon warships obscured by the shadows of the surrounding hills, ready with archers and cannons, and the
melee-based Japanese found themselves unable to fight effectively and break through the superior Joseon ranged fire. The unpredictable current eventually wreaked havoc on the Japanese; their ships found themselves unable to maneuver and collided with each other when the tide reversed, while also presenting a perfect target for the Joseon naval artillery. Admiral Yi was astonishingly able to rout a force that outnumbered him more than 25 to 1 in ships alone. About 31 of the 333 Japanese ships that entered the Myeongnyang Strait were destroyed or damaged. Joseon losses on the other hand were around ten casualties and no ships lost.
Kurushima Michifusa was killed on his flagship by Joseon archers; his body in its ornate armor was fished out of the water and his severed head was put on display to further demoralize the Japanese fleet.
Final battle and Admiral Yi's death On December 15, 1598, a huge Japanese fleet under the command of
Shimazu Yoshihiro, was amassed in
Sachon Bay, on the east end of Noryang Strait. Shimazu's goal was to break the allied forces' blockade on
Konishi Yukinaga, join the two fleets, and sail home to Japan. Admiral Yi, meanwhile, knew exactly where Shimazu was, after receiving reports from scouts and local fishermen. At this time, the Joseon fleet consisted of 82
panokseon, with 8,000 soldiers under Admiral Yi. The Ming fleet consisted of six large
war junks, 57 lighter war galleys and two panokseon given to
Chen Lin by Admiral Yi, with 5,000 Ming soldiers of the
Guangdong squadron and 2,600 Ming marines who fought aboard
Joseon ships. The battle began at two o'clock in the early morning of December 16, 1598. Like Admiral Yi's previous battles, the Japanese were unable to respond effectively to the Korean's tactics. The tightness of Noryang Strait hindered lateral movement, and Yi's maneuvers prevented the Japanese fleet from boarding their enemies' vessels, their primary naval tactic. As the Japanese retreated, Admiral Yi ordered a vigorous pursuit. During this time, a stray
arquebus bullet from an enemy ship struck Admiral Yi, near his left armpit. Sensing that the wound was fatal, and fearing a repeat of the Battle of Chilchonryang, the admiral uttered, "
The war is at its height – wear my armor and beat my war drums. Do not announce my death."
Comrade Chen Lin During the battle,
Chen Lin and Yi were friends and allies who helped and rescued each other several times. When Chen Lin called for Admiral Yi to thank him for coming to his aid, he was met by Yi Wan, who announced that his uncle was dead. It is said that Chen himself was so shocked that he fell to the ground three times, beating his chest and crying. News of Admiral Yi's death spread quickly throughout the allied fleet and both Joseon and Ming sailors and fighting men wailed in grief. ==Legacy==