Yi was 47 years old, at the height of his powers, and a man whose military talents and reputation for honesty made him both hated and admired by his peers.
After completing the destruction of the Japanese fleet at Tangpo, Yi and Won Kyun spent the next two days scouring northern Koje Island and then west along the mainland coast, searching for more enemy ships. Not a single Japanese vessel was sighted. On July 12 Cholla Right Navy Commander Yi Ok-ki at the head of twenty-five large warships finally caught up to Yi Sun-sin, bringing the combined strength of the Korean fleet to fifty-one large battleships plus many smaller craft. The arrival of these ships and reinforcements raised the spirits of Yi Sun-sin’s tired men immeasurably.
Then came news: enemy ships at Tanghangpo.
Tanghangpo, at the head of a narrow inlet ten kilometers from the open sea, was a potentially dangerous place to take on the Japanese. Yi Sun-sin, Yi Ok-ki, and Won Kyun accordingly approached it with caution. A scout was first sent ashore to inquire whether the bay was wide enough for their ships to maneuver. It was. Then a small advance party of warships was sent through the narrow neck of the inlet to locate the enemy. This was soon done and signal arrows sent up, calling the rest of the fleet forward. Leaving four of their ships behind to pick off any Japanese ships that attempted to flee, the two Yis advanced into the bay at maximum speed.
They arrived at Tanghangpo to find twenty-six enemy ships anchored along the shore: thirteen small and four medium-sized vessels, plus nine large ships as big as a Korean panokson. All of them were painted black except for the largest one, the flagship. It had a three-story pavilion upon its deck that was painted in red, blue, and white and wrapped in a skirt of black cloth, and looked to Yi Sun-sin like a Buddhist shrine. Four of the vessels flew large banners painted with the characters namu myoho renge kyo: “Glory to the Holy Lotus,” the incantation of the Buddhist Nichiren sect.
The Korean fleet, unable to form a straight battle line in the confines of the bay, arranged itself this time in a circle. With the turtle ship again leading the way, the battleships took turns sweeping in to loose their fusillades of cannonballs, iron bolts, and fire arrows upon the Japanese, then fell back to reload as the next ship in the circle moved in. The relentless pressure soon had the Japanese on the defensive, so much so that Yi Sun-sin realized they would likely abandon their ships and flee inland, depriving him yet again of the opportunity of destroying them completely, not just their ships but their crews as well. He therefore gave the order to fall back in a feigned retreat, coaxing the Japanese to counterattack, out into open water. The ploy worked perfectly. The Japanese, assuming that the battle was turning in their favor, left the relative safety of shore and advanced into the bay in pursuit. When they were just where he wanted them, Yi ordered his ships to come about and surround the Japanese, and blast their ships to splinters. The large flagship with the pavilion on top drew the heaviest fire. According to Lee Sun-sin, a trusted captain in Yi Sun-sin’s Cholla Left Navy, “The enemy Commander, aged about 24 or 25, of strong physique, wearing magnificent dress, stood alone holding a long sword in his hand and fought to the last without fear as he directed his eight remaining subordinate warriors. I shot an arrow at him with all my might, but it was not until he had been shot through and through with more than ten arrows that he shouted loudly and fell, after which his head was cut off. The remaining eight Japanese were also shot down and beheaded.” Soon all the Japanese ships had been sunk or set ablaze. Only a few survivors managed to swim to shore and escape into the hills. All that remained was for Won Kyun to move forward to hack off the heads from the enemy dead.
For the next four days the Korean fleet sailed from port to port along the coast of central Kyongsang Province, searching for additional enemy squadrons to attack. They spotted a few ships scurrying back toward the east and safety but were unable to run them down. It soon became apparent that the Japanese navy had retreated to Pusan and that the fighting was over until they decided to venture west again. On July 18, therefore, Yi Sun-sin, Yi Ok-ki, and Won Kyun dissolved their combined fleet and returned to their respective ports to rest and rearm for the next campaign.
At the time of their parting Won Kyun expressed a desire to get together with Yi Sun-sin immediately to write and submit a joint battle report. Yi stalled, saying that there was no need for haste, and presumably leaving Won to assume that they would prepare a joint report a little later on. Yi then went ahead and wrote a lengthy and detailed dispatch on his own without any input from Won. In it he once again had phenomenal numbers to report: seventy-two enemy vessels destroyed at the cost of not a single Korean ship; eighty-eight Japanese heads taken and countless others killed, against Korean losses of only eleven killed and twenty-six wounded. Yi was careful to explain that the low head count was due to standing orders he had issued to his officers not to waste time with this self-aggrandizing practice, the sole purpose of which was to win glory and rewards. Yi promised that he would recommend those who fought well, “even though they cut off no heads.” And indeed, in this and every other battle report he sent to the Korean court, he included the names of all the officers he considered worthy of reward, with urgings that these rewards be issued as soon as possible to encourage their morale. This was in line with the teachings of the ancient Chinese military classics, as well as being plain common sense: “Beneath fragrant bait there will certainly be dead fish. Beneath generous rewards there will certainly be courageous officers.”
As for Won Kyun, Yi Sun-sin made no effort to cast him in a favorable light or secure for him a reward. On the contrary, he pointed out that the Kyongsang commander had lost his entire fleet at the start of the invasion and so had nothing to command in the recent campaign, and by inference nothing to contribute. This upset Won when he heard of it, and resulted in the tensions that already existed between the two men giving way to open hostility. Henceforth they would submit separate battle reports. Just as hurtful as Yi’s words, however, was the fact that recognition was not forthcoming. As Yi Sun-sin was rewarded with letters of commendation and one promotion after another—to court rank Junior 2B in June, Junior 2A in July, and Senior 2A in September—Won Kyun received nothing. Won evidently made his dissatisfaction known to the government, for in early October it was recommended that he and Yi Ok-ki receive promotions and letters of commendation in recognition of their service alongside Yi Sun-sin.
Why did the Korean navy under Yi Sun-sin enjoy such superiority over the Japanese? First, the Koreans had better ships. With their two banks of sculling oars, Yi’s turtle ship and board-roofed ships were faster and more maneuverable than anything the Japanese possessed. They were more heavily built, with sides and roofs of thick wooden planks that were impervious to Japanese muskets. They were well equipped with large cannons that could blast a stone or iron ball clean through a Japanese hull. With these three strengths a Korean battleship could close to within just a few meters of an enemy vessel and smash it to splinters with little fear of counter-fire, for the Japanese navy at this point did not possess cannons in any appreciable number. It only had lightweight muskets, an effective weapon against the flesh of Korean soldiers and horses on land, but of little use against the thick wooden shell of a Korean battleship.
The Koreans also benefited from a more unified system of naval command. In these early sea battles of the war, Cholla Left Navy Commander Yi Sun-sin naturally took the de facto lead of the Korean navy in the south—he was fifteen years older than thirty-two-year-old Cholla Right Navy Commander Yi Ok-ki and correspondingly more experienced—a role that would be formally recognized by the court in the coming months with his promotion to the special rank of supreme naval commander. On the Japanese side there was no one in a comparable position of overall authority. The Japanese navy was composed of a loose assembly of squadrons, each belonging to and commanded by a separate daimyo, each looking out for his own interests, each deciding for himself what he would and would not do. No one, in other words, was bound very closely by orders. There was in fact only one man with enough authority to compel these naval commanders to work together to achieve a single objective, and that was Hideyoshi. But Hideyoshi was not on the scene. He was still at Nagoya, ostensibly waiting on the weather. In his absence the commanders of the Japanese navy thus had to work out among themselves ways for dealing with the Korean threat, with egos and rivalries and jealousies all coming into play, a fact that hampered their ability to face down Yi Sun-sin’s united fleet.
All these advantages that the Koreans enjoyed at sea—better ships, better guns, and a more unified system of command—are evidence of a more sophisticated understanding of naval warfare than that possessed by the Japanese. In 1592 Hideyoshi and his commanders still had a medieval conception of warfare at sea. To them it was little more than an extension of warfare on land, with ships serving as fighting platforms from which opposing forces tried to pick one another off with arrow and musket fire, followed by grappling and boarding to finish off survivors. The goal, in short, was to kill enemy sailors, not sink enemy ships. They thus armed their vessels accordingly, with lightweight arquebuses, not heavy cannons.
The Koreans saw things the other way around. For Yi Sun-sin, Yi Ok-ki, and Won Kyun the primary purpose of naval warfare was to destroy enemy ships. They thus armed their panokson and kobukson with cannons to sink them and fire arrows to burn them. Kill an enemy, after all, and you only kill one man. Destroy an enemy ship, however, and you destroy much of its crew as well, leaving the rest floundering in the water where they then could be hacked to death.
If the immediate purpose of war is killing and destruction, then the Japanese were better at it on land, while the Koreans excelled at sea.