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Admiral Yi Sun-shin, the Turtle Ships and Korean Culture in Early Modern World History

Written by Marc Gilbert
Professor of History, North Georgia College & State University

Yi Sun-shin Takes Command

Yi Sun-shin was neither caught unaware nor unprepared by the Japanese assault. Upon his arrival in southern Korea, Yi Sun-shin immediately set about his new duties as naval commander. He had long studied the strengths and weaknesses of both Korean and Japanese naval practices and weapons. Japanese naval power was based on their greatest strength — expert samurai swordsmen and bowmen. To maximize their strength, the Japanese built broad-beamed ships that carried a large number of soldiers. Their strategy, which, as one modern authority has noted, was as old as the Battle of Salamis in 480 BCE., was to approach enemy vessels as closely as possible and rake them with arrow fire until the enemy’s decks were clear enough for the Japanese swordsmen to sweep aboard and do battle with the remaining opponents. Stiff resistance was met with fire arrows fired by the bowmen, though still necessarily firing at close range. More recently, though the Japanese had chosen not to mount more than one cannon to each of their ships, they were filling their vessels with musketeers. The range of Japanese muskets was no greater than that the bowman could achieve with their arrows, but the bullets fired by muskets had much greater penetrating power. According to some Japanese sources, these ships, called Atakebune, were ironclad, very slow and thus ill-suited to handle anything more than coastal operations.

Like the builders of the caravel in Western Europe, the Koreans built ships with “castles” or enclosures to better protect their crews from attack by arrows and muskets. Korean records suggest that a ship called a “turtle boat” [Kŏbuksŏn] was under construction as early as 1414, but by the time of Yi Sun-shin’s appointment, no Korean ship of any type was capable of defeating the Japanese. Yi Sun-shin lost no time in urging the local boatyards to rectify this problem. Though there is no evidence by which to gage their progress, within months they produced a vessel “that so thoroughly nullified the enemy’s weapons and tactics that, in Yi Sun-shin’s hands, only a few of the new ships were necessary to secure naval dominance in the seas around Korea.” His ultimate success was to become so entwined with Korean national pride that they led to often outlandish claims. As Underwood notes:

It is often asserted that [the Turtle Ships] were the world’s first armored or ironclad vessels; some modern writers even describe them as the world’s first submarines! They certainly were innovative in design, but, despite Korean’s brilliance in metal-working, it is unlikely that the Turtle Ships carried any metal armor — their offensive advantage over the Japanese was their speed and multi-cannon armament: heavy ship armor would have slowed the ships and, in combination with the as many as 40 cannon they mounted, would have lent them so great a weight as to sink the ship. Armor plates on the ship’s upper deck would have certainly done so, as the ships were without keels and would have been so top-heavy as to have easily capsized.3

Since there were probably not many more than a dozen of these vessels operational at one time and possibly as few as three in service on occasion, Underwood contends that “the emphasis on the originality of the ship’s design “diminishes Admiral Yi Sun-shin’s far greater achievement. It was his development of thoroughly modern ship-fighting tactics that perfectly exploited his new ship’s design that was a greater cause of Korea’s naval success against the Japanese than the ships themselves.” After all, “when Yi Sun-shin was temporarily superseded in command, his successor was ignominiously defeated while deploying the same forces in battle. Yi Sun-shin’s true genius lay in the “new ships’ design as an expression or extension of Yi Sun-shin’s revolutionary tactics.”4

Yi Sun-shin’s design for his Turtle Ships addressed the fundamental problem posed by the Japanese tactics and weapons: how could they avoid being shattered by close range bow and musket and fire and boarded by the world’s best swordsmen? The answer lay in speed and longer range fire-power. Yi Sun-shin’s Turtle ships were almost twice as long and half as wide (110 feet by 38)5 as their Japanese counterparts, making them much faster through the water. And since his cannon could outrange Japanese musket balls, he could effectively engage his enemy at his discretion, standing off from them and pounding them into small pieces of flesh and wood. These boats had as many as forth 3-inch (or thirty-six pound) cannons firing through hatches along its side. Another cannon was mounted in the mouth of the good luck-attracting dragon's head carved into the prow, while still another was mounted beneath the stern transom.

In retrospect, Yi Sun-shin’s development of the first “stand-off” weapon was a simple enough proposition, except that Yi Sun-shin shares with Sir Francis Drake credit for being the very first men to abandon the grapple-board-and have-at-them style of naval fighting that had gone unchanged for perhaps two thousand years and adopt in its stead the form of naval warfare later pursued from Trafalgar to Jutland and from Cape Matapan to Leyte Gulf.

Yi Sun-shin anticipated that his enemies would ultimately adjust their own war-fighting strategy to meet this new challenge: Japanese ships came to mount more cannon of their own. However, like Drake, Yi Sun-shin always remained a step ahead of his foe. His forces were, for example, also the first to adopt an “in line ahead” (Yi Sun-shin called it “holding onto each other’s tail), a sailing protocol that enabled each ship to bring its guns to bear upon the same targets as they passed them in turn.

He also deployed a tactic called ‘drawing the fish into the net,” with the feigned retreat to in order to draw entire Japanese fleets into position to attack, so few could avoid combat or otherwise escape the engagement. It is for this reason relatively few Japanese ships survived an engagement with Yi Sun-shin forces unscathed.

As brilliant as his tactics may have been, Yi Sun-shin also knew that he could not always dictate the rules of engagement. There would be times when his forces would have to come to close quarters with Japanese ships and face their intense close-in fire and skilled boarding parties. Yi Sun-shin addressed this problem through the very structure of the Turtle ships themselves. Building on evolving Korean practice of cannon use (introduced from China in 1373) and protection for crews, Yi Sun-shin entirely enclosed his oarsmen and gun crews in iron-bound four-inch thick wood deck planking impervious to arrows and musket fire. A recent work by admittedly non-naval architects argues that the exposed upper planks may have been covered by very thin sheets of metal, which may have given rise to the idea that the ships were made of metal or armored,(Shim Sun-ah, “New Book Sparks Controversy Over 'Turtle Ship,”Yonhap News Service, February 2, 2005.) but Korean deck wood seems to have been more than adequate to this task and obviated the added weight. However, more importantly, and most likely Yi’s own idea was that the curved upper-most deck acted as a roof protecting the crew, who were trained to shove their own spear points through slots in the decking that were concealed by thatch strewn over the deck. It is though that “Japanese soldiers leaping upon that decking would find themselves either impaled upon these blades or sliding off the rounded upper-surfaces into the sea.”

my note- As widely known he had about 20 fights on the sea against Japan and led all the fights to the win. In the Battle of Myeongnyang, he faced the biggest adversity in his life ; he had only 12 ship left to fight large number of Japanese soldiers. Everyone thought it is a reckless challenge and even the king did not trust him. Lee Sun Shin felt deep depression and thought about giving up the fight. However, he started to make tactics and gave the soldiers training as he believed himself and his navy. He finally won the fight and is remembered as a hero who saved our country form Japanese. I will use him as my first reason (RESILIENCE)