If there is no evidence in the historical record that the kobukson was ironclad, where did this idea come from? One hypothesis is that it may have come from the West. The first tales of Yi Sun-sin and his turtle ship to reach Europe and the United States were carried back by Westerners who visited Korea as it started to open to the world in the late 1870s. A British naval expedition to Korea in 1883, for example, included an account of the curious vessel in its official report, which subsequently appeared in a Chicago newspaper. Ensign George Foulk of the U.S. Navy heard similar stories during his wide-ranging travels on the peninsula in 1884, and actually saw what locals claimed to be the ribs of a turtle ship lying in the sand at Kosong on the coast of Kyongsang Province. To a Westerner of this period, these descriptions of an indestructible warship with a roof like a turtle’s back would have conjured up an immediate association: the Confederate ironclad the Virginia (a.k.a. the Merrimac) and its Union counterpart the Monitor which had battled each other in the American Civil War some twenty years before. It is possible that the inevitable comparison of Yi’s warship to these two ironclads of recent memory led to the assumption that it too was fitted with iron plates and not simply “armored” with a heavy timber shell. This progression from casual comparison to statement of fact can be roughly charted. In his 1892 account of Hideyoshi’s invasion, George Heber Jones wrote that “aided by his famous ‘Tortoise Boat,’ a prototype of the ‘Monitor’ of the American Rebellion, [Yi Sun-sin] literally swept [the Japanese] off the coast waters of the peninsula.” William Griffis took this a step further in 1894 in Corea. The Hermit Kingdom, describing Yi’s ship as “apparently covered with metal.” By 1905 the transformation to fact was complete. “Its greatest peculiarity,” wrote Homer Hulbert of the turtle ship in his History of Korea, “was a curved deck of iron plates…. [I]t anticipated by nearly three hundred years the ironclad war ship.”
Yi Sun-sin’s armored kobukson thus went from being regarded as “like” the ironclads of the American Civil War to being itself an ironclad, an assumption that gained weight the more often it appeared in print. It was an assumption that was readily accepted by the Koreans, who were then trying to deal with a flood of Western pressures and innovations that was making them appear to the world as a weak and backward people. In this atmosphere of vulnerability the idea that a Korean had invented the ironclad ship nearly three centuries before was immensely appealing, for it demonstrated that Korea was not a backward country, but in some things had actually preceded the West. The belief that Yi Sun-sin’s kobukson was an ironclad ship thus resides firmly in the consciousness of Koreans today, despite the lack of evidence to support the claim, for it is more than just a historical artifact. It is a symbol of national pride.
One of the more distinctive features of the turtle ship was the impressive dragon’s head that adorned its bow. This head is depicted in modern-day models and illustrations in an attractive upraised position like a cobra rearing to strike, together with the explanation that smoke from burning gunpowder and sulfur was emitted from the dragon’s mouth to terrorize the enemy and obscure the vessel’s movements. In his own description of the craft, however, Yi Sun-sin states that a cannon could be fired through the mouth, something that could not have been done if the head was upraised. It must have projected straight out from the bow in a less majestic manner.
The genesis of these two images is found in The Collected Works of Yi Sun-sin published in 1795, a compilation of Yi’s war diary and official dispatches, additional accounts penned many years after his death, and commentary written by the editors themselves. Among this latter material are two illustrations of the turtle ship. The first, labeled tongjeyong kobukson, is an estimation of what the vessel originally looked like in the early fifteenth century, with a dragon’s head projecting straight out from the bow. The second illustration, labeled Cholla chwasuyong kobukson, depicts a turtle ship that was still extant in 1795, anchored at Yosu, home port of the Cholla Left Navy, which was said to resemble the revised turtle ship Yi Sun-sin developed in 1592. It has two dragon heads: an upraised one above, and a downward-projecting one below that seems to emerge from the bow just beneath the fighting deck where the cannons would have been. If a vessel resembling the Cholla chwasuyong kobukson did see service in the Imjin War, then it may have been a later innovation, one of the several additional turtle ships Yi had constructed after 1592. The editors of Yi’s Collected Works may also be wrong: the illustration may depict a vessel built long after the war. The only description that Yi himself has left us indicates that the dragon’s head on his turtle ship projected straight out from the bow, as on the tongjeyong kobukson. If his ship had two heads like the Cholla chwasuyong kobukson, then the lower head must have projected forward and been positioned higher, at the gun deck.
After leaving his home port of Yosu on July 8, Yi Sun-sin met Won Kyun at Noryang Bay and the two men once again formed a combined fleet. From there they headed toward Sachon, a port dangerously close to the Cholla border, where according to reports Japanese ships had already arrived.
By this point Yi evidently had little use for the Kyongsang Right Navy commander and his fleet of four ships, for he gave Won the job of “finding Japanese killed by arrows or bullets anywhere on the battle-ground, and [cutting] off their heads.” Yi personally saw no value in this glory-seeking practice and instructed his own men not to waste their time with it. “Rather than cutting off the heads of a few dead enemies,” he told them, “you are expected to shoot many of the living enemy. My eyes will judge who fights best.” But the job seems to have suited Won Kyun very well. It gave him the battle honors he craved while keeping him out of the actual fighting, where he was apt to do more harm than good.
Yi and Won arrived at Sachon later that same day to find more than four hundred enemy soldiers fortifying positions on the rocky hill above the port. Red and white banners had been raised in a line stretching three kilometers along the coast. A number of ships, all flying white ensigns, rode at anchor just offshore, including twelve large “pavilion vessels” with high castles built on their decks. Yi did not want to attack the ships where they lay. Such a close approach to shore would expose his force to enemy fire from the heights above and put his heavy ships at risk of running aground with the ebbing tide. He preferred to deal with the enemy in open water, where there would be ample room to maneuver. Suspecting that the Japanese might feel overconfident at the sight of his mere twenty-three ships, Yi made a tentative entrance into the bay, then turned to retreat. Sure enough, more than half the Japanese on shore rushed to their ships to pursue the fleeing Koreans. Soon they were just where Yi wanted them, in the middle of the bay.
And so the battle began. With the impregnable turtle ship captained by Na Tae-yong leading the way, the speedy Korean warships cut a swath through the lighter, slower, less maneuverable Japanese craft, ramming them, blasting away with cannon, setting them ablaze with fire arrows, and raining death upon their unprotected crews. The Japanese fought back as best they could, but their bullets and arrows were of little use against the heavy plank tops and sides of Yi’s board-roofed ships and turtle ship. Seeing his men begin to hesitate, Japanese commander Wakizaka Yasuharu is said to have leapt onto the gunwale of his flagship and cried, “These vessels the enemy are using are only like our mekura-bune (blind ships). What is there to worry about? Board them and show what you are made of!” According to this Japanese account of the battle, Wakizaka and several of his retainers then managed to draw in one of the Korean warships with a grappling hook and scramble onto its roof, but were beaten back by withering counter-fire.
The Japanese remaining on shore, meanwhile, began to direct musket fire at the Koreans to aid their own fighting sailors. Looking up at the hill, Yi Sun-sin could make out a number of Koreans—identifiable presumably by their native clothing—standing alongside the “robbers.” This caused him such rage that he threw his usual caution aside and ordered his oarsmen to dash toward shore, where he proceeded to hammer the enemy positions with his “heaven” and “earth” cannons. The fusillades eventually drove the enemy from the bluff, but exposed Yi’s flagship to heavy musket fire. Yi himself was struck by a bullet in the left shoulder, and blood flowed profusely down his torso and leg. He concealed the wound until the fight was over so as not to alarm his men—an indication of the importance that the sheer force of his personality played in galvanizing his men into an effective fighting force. Several others were also wounded in this engagement, including Yi’s turtle ship builder and captain, Na Tae-yong, but no one mortally. Later accounts claim that after the battle Yi dug the bullet out of his shoulder with a dagger, but this would seem to be an apocryphal touch, designed to inflate the Yi legend; according to Yi’s own account the bullet passed cleanly through his shoulder and exited out the back. The wound must nevertheless have been serious and painful, and the fact that Yi would continue his campaigning for several more days and not mention it again in his diary is in itself remarkable.
With the daylight nearly done and all the larger Japanese vessels destroyed, Yi withdrew his force to the open sea to pass the night. Before departing he left a few of the smaller enemy ships intact and in place as a lure for the Japanese who had fled inland. Eager for total annihilation, he hoped that these scattered remnants would attempt to use the vessels to return to Pusan, thereby offering him a second chance to destroy them out on open water.
On the following morning, July 9, word arrived of a squadron of Japanese ships sighted a little farther to the east, at the harbor of Tangpo. The Korean fleet immediately made off in that direction, arriving before noon to find twenty-one enemy vessels at anchor along the beach, nine of them as large as the Koreans’ own board-roofed ships. One of them appeared to be the flagship of the fleet. A pavilion ten meters high was erected on its deck, “surrounded by a red brocade curtain with a large Chinese character ‘Yellow’ embroidered on each of the four sides. Inside the pavilion was seen a Japanese commander with a red parasol in front. He showed no expression of fear, like a man resigned to death.” This was Kurushima Michiyuki, one of the daimyo leading the advance party of the Japanese navy west to the Yellow Sea. With him was a force of seven hundred fighting men, plus crews. It would be the last day of his life.
Once again the turtle ship led the way into the fray, striking out at every vessel it passed. One of the panokson closed with Kurushima’s flagship. An arrow struck the Japanese commander in the brow; then a second pierced his chest and sent him toppling off his pavilion, whereupon one of Yi’s officers hacked off his head with a sword. The sight so unnerved the rest of the Japanese force that they abandoned the fight and fled into the hills, leaving the Koreans once again to burn their ships unopposed.
Aboard one of the Japanese ships that fell to the Koreans that day, a curious piece of booty was recovered and carried to Yi Sun-sin. It was a gold fan packed in a black lacquer case. Written on the center of the fan were the words, “sixth month, eighth day, Hideyoshi,” to the right of this “Hashiba Chikuzen-no-kami,” and to the left “Kamei Ryukyu-no-kami.” Yi took these inscriptions to mean that “the Japanese commander, whose head was cut off, must be Chikuzen-[no-kami], the garrison commander of Chikuzen.” He was mistaken. “Hashiba, Lord of Chikuzen” was in fact the appellation used by Hideyoshi himself ten years before. In 1582, when he was still consolidating his hold over the territories of his recently deceased master, Oda Nobunaga, Hideyoshi secured the allegiance of Kamei Korenori, a fellow daimyo in Inaba Province, by promising to give him the Ryukyu Islands whenever they should be conquered. As proof of his word, Hideyoshi took his fan from his belt and inscribed it with his and Kamei’s names, the date, and the words “Ryukyu-no-kami,” “Lord of Ryukyu.” This fan remained a prized possession of Kamei’s for the next decade and was now evidence of his presence at the Battle of Tangpo, alongside Kurushima. Kamei lost all five ships under his command that day, but managed to escape with his life.