㉖ Who Was Son Mun-uk, the Man Who Picked Up the War Drum After Admiral Yi's Death?

In the predawn hours of November 19, 1598, in the middle of the waters off Noryang, Admiral Yi Sun-sin was struck in the chest by an enemy bullet and fell. A man standing beside him stopped the cries of grief around him, covered the body with a garment, and took up the war drum himself to urge the attack onward. The soldiers, believing their commander had not died, found their courage again, and the battle ended in a great Joseon victory.

Yi Sun-sin, while personally firing arrows at the enemy, was struck in the chest by an enemy bullet and collapsed on the deck of his ship; his son wished to cry out, and the soldiers grew alarmed. Yi Mun-uk, who was nearby, stopped the crying, covered the body with a garment, and beat the drum to press the attack, so that all the soldiers, believing Sun-sin had not died, found courage and pressed the assault. The enemy was at last utterly defeated, and people all said, ‘The dead Sun-sin drove off the living enemy.’ (Annals of King Seonjo, 27th day of the 11th month, Seonjo 31)

Yi Mun-uk (李文彧). These three characters name the man who stood by Admiral Yi in his final moments.

Today, though, this figure is generally known by a different name: Son Mun-uk (孫文彧). He had two different names, and for a time the court itself did not even know whether he was Korean or Japanese.

Who was he?

“Yi Mun-uk” or “Son Mun-uk”?

In the Annals, his name changes over time. From April 1597 to September 1598, he consistently appears as “Yi Mun-uk.” But starting with an entry dated November 2, 1598 -- sixteen days before the Battle of Noryang -- recording that Admiral Yi had sent him on Yi's own orders to the camp of the Ming admiral Chen Lin, he suddenly appears as “Son Mun-uk.” This lines up exactly with the point at which he had fully left the Japanese camp and taken a formal place within the Joseon forces. Given that other Japanese-born men who defected to Joseon (called hangwae) often received newly granted Korean surnames, it seems likely he acquired the surname “Son” (孫) around this time.

The passage quoted above describing the victory at Noryang, however, is part of a commentary the Annals' compilers added afterward in summarizing the event -- which is likely why his earlier name, “Yi Mun-uk,” reappears there specifically. Across the Annals as a whole, “Yi Mun-uk” appears five times and “Son Mun-uk” forty times. In this post, when describing the scene on the day of the Battle of Noryang itself, I'll use the name as it appears in the original text, “Yi Mun-uk,” while noting that this is the same person as “Son Mun-uk.”

Letters from the Japanese Camp -- A Man of Unknown Identity

Yi Mun-uk first appears in the Annals in April 1597, a full year and seven months before the Battle of Noryang. According to a report the Gyeongsang provincial governor Yi Yong-sun submitted to the court, he had begun sending secret letters from inside the Japanese camp, passing information to the Joseon side. One of those letters introduced him this way:

Mun-uk is skilled in letters and possesses courage; when the Kanpaku (Toyotomi Hideyoshi) tested his talents, he grew deeply fond of him, at once called him his adopted son, gave him the ruler's own surname, and rewarded him with a thousand seok of rice. ...As his favor grew deeper on this account, other officials grew jealous and falsely accused him of an affair with Hideyoshi's concubine; but Hideyoshi said, ‘There must be some reason behind such slander, but his talent and achievements are such that I cannot bring myself to kill him,’ and made him a deputy commander under Konishi Yukinaga, so that he could go on to earn merit. (Annals of King Seonjo, 25th day of the 4th month, Seonjo 30)

No Japanese-side record confirms the claim that he became Toyotomi Hideyoshi's adopted son, and the general view is that he inflated his own worth while preparing to defect. That he served as a deputy commander under Konishi Yukinaga, though, is confirmed by Japanese records and appears to be true.

The court's response was cool-headed. That June, when King Seonjo asked, “Whose son is Yi Mun-uk?” Chief State Councilor Ryu Seong-ryong answered, “It cannot be known” (Annals of King Seonjo, 2nd day of the 6th month, Seonjo 30). Even the Joseon court itself did not know who he really was. Still, King Seonjo acknowledged his usefulness as a source of intelligence, saying, “A man like that ought to be brought over to us; even if he stays there and passes on enemy intelligence, that would still be fine.”

And it would be another year and three months before his formal defection was reported to the court at all. Only on September 23, 1598, does a report from Won Sin, the defense commander of Jeolla Province, record that “the commoner scholar Yi Mun-uk, who had attached himself to the enemy at Namhae, came out from the enemy camp” and provided information on Japanese troop strength and strategy. From his first contact to his formal defection, some seventeen months passed -- during which he remained inside the Japanese camp, passing information to Joseon, belonging fully to neither side.

Into Admiral Yi's Circle

Exactly when Yi Mun-uk came under Admiral Yi's command isn't recorded even in the Nanjung Ilgi, which breaks off after its final entry on October 7, 1598, leaving a gap of about a month and a half before the Battle of Noryang. The Annals, though, record that sixteen days before Noryang, on November 2, he entered the camp of the Ming admiral Chen Lin on Admiral Yi's own orders, to discuss a plan for taking the Japanese fortress at Suncheon. His experience moving in and out of the Japanese camp, and his language skills, appear to have made him useful in coordinating between the Joseon and Ming forces in the war's final stretch.

Seventeen days later, he would be at Admiral Yi's side as the admiral drew his last breath in the waters off Noryang.

After Noryang -- A Dispute Over His Credit

His role continued even after the battle ended. As the Ming admiral Chen Lin pursued the retreating Japanese, setting fire to the hills and marshes of Namhae Island, Joseon civilians hiding there began suffering harm as well.

Son Mun-uk explained the situation in detail to Admiral Chen Lin, and only then did the admiral send out his command flag and order it stopped. (Annals of King Seonjo, 7th day of the 12th month, Seonjo 31)

Supreme Commander Gwon Yul, too, reported his achievements to the court:

After Commander Yi Sun-sin fell in battle, Son Mun-uk and others handled the situation with quick judgment, so that the men fought on desperately despite the danger. Mun-uk himself climbed onto the deck, surveyed the enemy's position, and directed the fighting; that Admiral Chen Lin avoided being overrun was also due to the achievement of our navy. (Annals of King Seonjo, 18th day of the 12th month, Seonjo 31)

The Office of Merit Assessment went further still, judging that “the merit of Son Mun-uk, who directed the troops and pressed the fighting onward, would not be excessive even if he were promoted, skipping ranks, straight to a senior court position” (Annals of King Seonjo, 25th day of the 12th month, Seonjo 31).

But this credit wasn't accepted unanimously at court. Three months after the Battle of Noryang, Yun Yang, a Ministry of Justice official, relayed a petition to the court from soldiers stationed with the naval commander's camp at Gogeumdo:

The achievement at Noryang was entirely won through Yi Sun-sin's own hard fighting; when he was unfortunately struck by a bullet, officers including Song Hui-rip and some thirty others covered the mouth of the grieving family so no wailing would be heard, and kept blowing the command horn just as if he were still alive, so that no one in the ranks knew of the commander's death, and in this way the victory was achieved. That Son Mun-uk -- a lowly soldier who had once been captured by Japan -- happened to be on the same ship and claimed the achievement as his own has left the entire army indignant. (Annals of King Seonjo, 8th day of the 2nd month, Seonjo 32)

The soldiers who were actually present at Noryang claimed that it was not Son Mun-uk but Song Hui-rip who had stopped the wailing and taken over command. The Annals thus preserve both claims side by side -- that the credit was Son Mun-uk's, and that he had stolen it from Song Hui-rip. The fact that he is described here as “a lowly soldier who had once been captured by Japan” suggests his status as a hangwae, a Japanese-born defector, likely deepened this conflict.

Even so, his achievement was eventually formally recognized by the court. The register of meritorious subjects records that “Son Mun-uk, of the rank Jeolchung Janggun, was enrolled as a second-class meritorious subject.”

After the War -- A Diplomatic Point Man Between Joseon and Japan

After the war ended, Son Mun-uk's life changed dramatically once again. In 1600, he took part in rebuilding fortifications in the northern Hamgyeong region, passing on the construction techniques of Japanese-style fortresses -- a structure he understood better than most, having once been held captive by the Japanese.

Then, from 1601 to 1607, he took on the practical work of intelligence-gathering and diplomacy between Joseon and Japan. In 1604, he crossed to Japan together with the monk-diplomat Yujeong and met with Tokugawa Ieyasu, who is said to have claimed he had no part in the Imjin War and returned some 1,300 Joseon prisoners of war. In 1607, he was promoted to a senior court rank for his service traveling to and from Tsushima (Annals of King Seonjo, 14th day of the 1st month, Seonjo 40).

A man once taken prisoner by the Japanese, a man who once sent secret letters of unknown origin -- after the war, he became the one bringing prisoners home and restoring diplomatic relations between the two countries. The very position that had let neither side fully trust him turned out to be exactly what made him useful moving between them.

A Name Erased From History

But the most striking twist surrounding his identity is that his achievement was later reassigned to someone else. The Annals of King Seonjo -- the primary record made at the time of the Battle of Noryang -- clearly credits him. But the later-compiled Revised Annals of King Seonjo rewrites the same scene:

Sun-sin said, ‘The fighting is urgent now -- do not speak of my death,’ and then breathed his last; his nephew Yi Wan concealed Sun-sin's death and urgently pressed the men to keep fighting, so that not even the army knew of it. (Revised Annals of King Seonjo, 1st day of the 11th month, Seonjo 31)

Admiral Yi's memorial stele inscription, and the Chungmugong Sijang -- a formal account of his life and honors written by Yi Sik, a member of the same Deoksu Yi clan as Admiral Yi -- likewise make no mention of Son Mun-uk, naming only Yi Wan. Why was he erased? Two circumstances stand out.

One is his own political conduct. In 1617, during the reign of Gwanghaegun, he is recorded as having spoken in support of deposing Queen Dowager Inmok (Diary of Gwanghaegun) -- a position that later became one of the justifications for the coup that overthrew Gwanghaegun, and those associated with it were purged afterward. The other is that Yi Sik, who compiled the Revised Annals of King Seonjo, belonged to the same Deoksu Yi clan as Admiral Yi himself. It's been suggested that he simply didn't wish to leave behind a record placing a hangwae defector, later targeted in a political purge, at the side of his own clansman Admiral Yi in his final moments.

The records surrounding his identity don't end there, either. The genealogical record of the Gyeongju Son clan, to which he is said to have belonged, states that he was the eleventh-generation descendant of Son Gyeong-won, that his given name in life was Son Yo-in, that he served as magistrate of Heungyang and deputy military commander of Suncheon, and that he died in battle during the war. But this directly contradicts his later, documented activity -- the 1604 trip to Japan, the 1607 promotion, the 1617 political statement. It's possible this refers to a different man entirely who shared the same name; the matter still needs further scholarly verification. Even the identity of the man in the Annals wavers again once set against his descendants' own genealogical records.

Rumors about him also circulate in popular fiction -- that he was a double agent secretly in league with Tsushima, or even that he tried to assassinate Admiral Yi. But these assassination theories have no historical basis. Several others -- Song Hui-rip, Yi Hoe, and Yi Wan -- were present in the command group at Noryang that day, and the matchlock muskets of the time took over a minute to reload and fire; the odds that he could have secretly shot the admiral himself are slim.

Closing Thoughts -- Who Was He, in the End?

Yi Mun-uk, or Son Mun-uk, is a man whose true identity was never fully settled, from beginning to end. A man the court itself said it could not know whose son he was; a man who, for over a year, belonged fully to neither the Japanese camp nor Joseon while passing along intelligence; a man the Annals say stood by Admiral Yi in his final breath -- and yet whose very credit for that moment was denounced by his own fellow soldiers as something stolen. After the war, he lived as a diplomat bringing prisoners home from both countries and restoring their relations, but before the tides of politics, his name was erased from a later-rewritten edition of the Annals, and his own descendants' genealogy tells a different story still -- that he had already died in the war.

Who he really was, no amount of gathering these records together can fully settle. But one thing is certain. He was a man who always stood at a boundary -- the boundary between Japan and Joseon, between prisoner and informant, between a man who earned credit and a man suspected of stealing it, between the man recorded in the Annals and the man erased from them. Even that brief predawn moment when he stood by Admiral Yi in his final instant -- whether it was truly his to claim, or someone else's -- the Annals themselves never manage to settle for certain.

But I choose to believe that he was there at Admiral Yi's side in his final moment, and that he took up the call to press the fighting onward in the admiral's place. I believe this because, when a historical dispute needs to be settled, I trust the weight that a primary source carries.

👉 Next post: ㉗ Comparing the Strength of the Four Naval Commands Before the Imjin War

— Momcheolhak