Keywords about Yi Sun-shin


The practice of justice

Admiral Yi Sun-shin practiced justice without any compromise of his integrity throughout his life. As a military officer, he always strictly distinguished between public and private affairs, and had no hesitation in speaking plainly to superiors or those in power about injustice. Such uprightness caused him to go through several hardships during his lifetime, but despite all of those challenges, he remained faithful to his principle of justice. In practicing justice, he was stricter on himself than on others. The following excerpt is from his report to the King, asking for his own punishment after his navy lost a ship at the battle of Ungcheonpo in 1593. In fact, the cause of the ship’s capsize was his subordinate generals not following his orders, yet he took full responsibility as a commander.

“A ship capsized and many were drowned. This is because I failed to adequately lead the soldiers, and my command was ineffective. I am waiting for punishment, prostrating myself on the ground.” (Tongseonilcheokgyeongbokhudaejoejang, April 6, 1593; Yi’s report to the King)

Also, he provided many subordinate generals with chances to make a distinguished contribution to naval battles. He strictly evaluated their operations to be recorded in his report to the King, so that they could be rewarded accordingly. Additionally, he hired engineers from various practical areas who were often treated contemptuously at the time, yet highly valued them and their work.

“My Lieutenant Jeong Sa-jun discovered a unique technology to make firearms, and developed some firearms with Yi Pil-jong (a marine in Nagan who used to be a blacksmith), An Seong (a private slave in Suncheon), Dong Ji (a temple slave in Gimhae), and Eonbok (a temple slave in Geoje) and others. The firearms, which they made by striking iron, have well-constructed gun barrels and are as powerful as Japanese firearms.” (Bongjinhwapojang, August 10, 1593; Yi’s report to the King) While reporting to the King about the production of the innovative firearms called ‘Jeongcheol chongtong’ in August of 1593, he wrote down the names of all the people who had contributed to the innovation, not only the name of his lieutenant but also the names of lowly slaves.

Admiral Yi Sun-shin lived all his life practicing justice by strictly adhering to his principles. He always led by example before he came to judge others. This attitude served as the foundation of his great achievements in saving the nation, highlighting his greatness.


Creativity is a primary value in the 21st century. Great leaders of all eras and countries are often well known to have had brilliant and creative minds. Yi Sun-shin in the 16th century was also a leader with excellent creativity. Yi’s creativity was reflected in his development of various innovative weapons including the Geobukseon battleship, outstanding naval tactics that became a part of world naval history, and effective ways to manage an army.

The first documentary record about the Geobukseon battleship appeared in 1413 under King Taejong (reigned 1400-1418). However, the Geobukseon at the time was very different in its structure and capability from the Geobukseon Yi redesigned 180 years later in the face of the Imjin War. The following is a documentary appearance of Yi’s Geobukseon, which was described in his report to the King about the battle of Dangpo on June 2, 1592.

“We put a dragon’s head on the front of the ship, and we can fire our cannons through its mouth. We stuck iron spikes on the shell (top), and designed it so that we could see outside from our position inside the battleship, but enemies cannot see us inside from their position outside the battleship. This battleship can rampage through hundreds of enemy ships in order to fire cannons. In this battle, I ordered an assault commander to lead the ship into the enemy fleet and bombard the fleet with cannons (Dangpopawaebyeongjang, June 14, 1592; Yi’s report to the King).

The Geobukseon as an assault battleship was designed by reforming the Panokseon battleship. The Panokseon was Korea’s primary battleship, designed with an upper deck that was shielded with a layer of wooden panels to be suitable for battles against Japan. Japanese naval forces preferred hand-to-hand combat after boarding enemy ships. The Geobukseon rammed into the enemy, broke the formation of the fleet, and bombarded the enemy fleet with cannons. It fatally damaged the Japanese fleet. Japanese forces were very afraid of the Geobukseon, calling it the blind ship.

Even during the continuous naval battles, Yi never neglected to develop new weapons. In August of 1593, he invented the Jeongcheol Chongtong, innovative firearms that combined the strengths of both Korean and Japanese firearms of the time. Yi’s creativity was also utilized in his management of the navy during the Imjin War. For all seven years of the war and almost single-handedly, he had to procure all the means necessary for the maintenance of the navy, including provisions and funds for the production of weapons and military training. For this purpose, he engaged in creative administration initiatives, including fishing, producing and selling salt, managing land called Dunjeon, and issuing certificates that charged a fee for the passage of coastal waters around the three provinces of Gyeongsang-do, Jeolla-do and Chungcheong-do. Using his experience as a Dunjeongwan, the officer in charge of managing Dunjeon, he gathered wandering people in Dunjeon to supplement the military personnel, and effectively procured provisions for the army. The following is Yi’s report to the King, stressing the need and benefit of managing Dunjeon.

“Provisions for the army are the most urgent need … [omitted] … Whether the government administers or lets tenants farm, there is a need to cultivate the reserved land. Or, you may use the defense soldiers in Suncheon and Heungyang to farm during peacetime and go on to battle during wartime. Then there will be no interference in their defense duty and it will be beneficial for procuring provisions” (Jojinsuryukjeonsajang, September 10, 1593; Yi’s report to the King).

Creativity provides the power to change weakness into strength, crisis into chance, and nothing into something. With his creativity, Admiral Yi Sun-shin constantly endeavored to stand up to numerous challenges in order to protect Korea against Japanese invasion and to maintain peace in East Asia. This made him a memorable hero who changed world history.

Undefeated naval record

Admiral Yi Sun-shin is a naval commander who was undefeated in at least 23 battles for 7 years during the Imjin War, starting from the battle of Okpo through the battle of Noryang. This is a great record rarely found in Eastern or Western history.

How was this legendary record possible?

1. Thorough preparedness
Upon his appointment as naval commander of the western part of Jeolla-do province, Yi Sun-shin thoroughly prepared for a war against Japan since he already foresaw its inevitability. He developed effective training strategies for the navy and produced powerful weapons based on his assessment of the strengths and weaknesses of enemies. The invention of the Jija and Hyeonja Chongtong firearms and the Geobukseon and Panokseon battleships were all in this context. Such comprehensive preparedness led him to victories in all of his naval battles. Also, the number of Korean casualties was significantly smaller than that of Japanese casualties.

2. Outstanding tactics
The battle of Hansando on July 8, 1592, is a famous naval battle that turned the tide of the Imjin War against Japan, and is considered as one of the world’s four greatest naval battles. The Strait of Gyeonnaeryang, where about 70 Japanese ships were anchored, was too narrow and unfavorable to the Korean Navy. Yi saw through these disadvantages and enticed the Japanese fleet into the wider sea. He then attacked the unwary enemies using his creative tactic called ‘Hagikjin’ or crane-wing formation. This battle concluded with the Korean Navy’s triumph. The battle of Hansando proved Yi’s ability as a brilliant strategist. He always studied and discussed strategies and tactics with his subordinate generals. Naval researchers in the East and the West have long praised and studied Yi’s distinguished naval tactics.

3. Distinguished war service
After establishing strategies on the basis of thorough preparations, he acted more bravely than anyone else in battle. The record is well known that he defeated 133 enemy ships with only 13 ships at the battle of Myeongnyang. When Korean Naval generals lost their fighting spirit and held back in going on to battle, Yi rebuked them and went forward to spearhead the battle. Encouraged by his brave initiative, the Korean Navy desperately fought against the Japanese at the risk of their lives, and triumphed despite being overwhelmingly outnumbered. Yi always led by example to encourage subordinates to do their best in battle.

Before every battle, he prepared thoroughly and devised effective strategies by using his remarkable insight in battle conditions. Yi’s glorious record of all victories and no defeats was possible because he always took the lead in battle with distinguished bravery, despite the danger that would await him.

Diligent record-keeping

A documentary record not only delivers the past to the present, but serves as a milestone to look back upon the past and plan for the future. People who leave accurate records of what happened at their time provide an invaluable gift to future generations. Admiral Yi Sun-shin is one of them, even though he was a military officer and not a professional scholar. He wrote a war diary (Nanjung Ilgi in Korean) for 7 years from 1592 until he died at the battle of Noryang in 1598. His war diary and the rough drafts of his war reports to the King (Imjin Jangcho in Korean) are celebrated as one of the three documentary classics of the Imjin War, along with Yu Seong-ryong’s Jingbirok, a chronicle of the Imjin War, and the Seonjo Sillok, the veritable records of King Seonjo. It must have been difficult for a soldier to maintain daily diary entries while engaged in life-or-death battles. Nevertheless, Admiral Yi Sun-shin diligently kept records of all the events during the Imjin War.

In the Nanjung Ilgi, Yi recorded the barracks life of his naval headquarters, naval tactics and situations in many naval battles, and various features of the lives of people in the Joseon Dynasty. He also straightforwardly wrote down his emotions and thoughts, making the diary the best resource to learn about him as a person. The diary was written in seven volumes, each volume completed every year from 1592 to 1598. The Nanjung Ilgi, designated as National Treasure No. 76, is kept in the Hyeonchungsa Shrine in Asan along with a collection of his letters (Seogancheop in Korean). Collections of Admiral Yi Sun-shin’s works have been published in many different editions, and are constantly read by researchers of Yi and by the general public.

Devoted love for the country and the people

Beginning his military career at age 32, Admiral Yi Sun-shin devoted his entire life to protect the country that he belonged to and loved. Regardless of his military rank, he did his best in his duty. After the breakout of the Imjin War, he protected the territorial waters of Korea as the head of the Korean Navy at the cost of his life. He faced many challenges in serving his country as a military officer. Trapped in false accusations by his superiors, he was demoted several times and served as a commoner in battle (the punishment of Baegui Jonggun) in 1587 and in 1597. Despite his outstanding accomplishments in naval battles, he even faced the threat of the death penalty as a criminal. However, these ordeals never affected his patriotism. Until his death on a ship during the battle of Noryang in November of 1598, he was firmly determined to serve his beloved homeland.

His love for the country was consistent with his love for the people. Even dangerous and precarious situations, his first priority was always for the safety of the people. He sincerely cared about people suffering hardships and tried to comfort them. Such humanitarian efforts were specifically described in several documentary records, including his war diary.

“If we burned all the Japanese ships and cornered them into a deadlock, they might slaughter our people. Hence, I decided to temporarily hold back at a distance of 1-ri away from them at night” (Gyeonnaeryangpawaebyeongjang , July 17, 1592; Yi’s report to the King)

In July of 1592, he triumphed over the Japanese at the historic battle of Hansando and at the battle of Angolpo. However, he allowed two remaining enemy ships to retreat. This was because he was afraid that the Japanese soldiers might kill ordinary people around the area for revenge. This choice of his was consistently observed in many later occasions. The following excerpt shows that he evacuated people in the urgent situation before the battle of Myeongnyang.

“I sent a messenger boat to the headquarters of the naval forces of western Jeolla so as to urge people to go up to the land quickly” (Nanjung Ilgi, September 13, 1597; Yi’s war diary).

Three days later, the Korean Navy faced 133 enemy ships with only a small fleet of 13 ships in the Strait of Myeongnyang. This naval battle was critical in deciding the recovery of the Korean Navy and the existence of the country. Before such a decisive battle, he still thought of the people first. Without a heartfelt love for the people, this attitude would not have been possible at such a critical moment. Throughout his life, he took care of people who had lost their homes, helping them make their living through fishing and farming while under the protection of the army.

The life of Admiral Yi Sun-shin had many challenges and obstacles in serving the country and the people of Korea. Despite all the hardships, however, he protected the country and looked after the people as always.

* References

1. Books
- Nanjungilgi, War diary of Admiral Yi Sun-shin, Song Chan-seop(2007)/Seohaemunjip
- Nanjungilgi, War diary of Admiral Yi Sun-shin , Roh Seung-seok(2005)/The Dong-A Ilbo
- Learn from CEO Yi Sun-shin, Kim Deok-su / Million House(2004)
- Yi Sun-shin and Imjin War(2007)/The society for the research of Yi Sun-shin/Bibong
- EnCyber &

-The Great Admiral Yi Sun-shin/Hyeonchungsa Shrine in Asan: