Korean troops during the Imjin War 
The Japanese Invasions of Korea proved to be damaging to not only Korea, but both Japan and China as well. Instead of strengthening his clan, Hideyoshi had bled his loyalist Toyotomi forces in a distant land (perhaps 150000 dead total out of 300000), resulting in its eventual destruction by the forces of Tokugawa Ieyasu. Ming China, already bleeding from long-running conflicts against the Manchus, faced even more financial strain on top of 30000 dead, though their Qing replacements benefited from the survival of the Chinese tributary system. Korea however suffered by far the most, with perhaps 260000 military dead; being the territory fought over, and with increased starvation, banditry and disease, some civilian death estimates run up to 1 million. Little known in the West, the Imjin War colors Korean-Japanese international relations to this day.
Dates 1592–1598
Location Korean Peninsula
Combatants Japan vs. Joseon Korea and China
Principal Commanders Japan: Daimyo Toyotomi Hideyoshi, Konishi Yukinaga, Kato
Kiyomasa, Konishi Yukinaga
Korea: King Sonjo, Sin Nip, Yi Sun Sin
China: Emperor Wanli (Zhū Yìjūn), Li Rusonh
Principal Battles Ch’ungju, Hansan-do, Busan, Pyokchegwan, Haengju, Chinji,
Ch’ilch’onnyang, Myongnyang, Noryang Strait
Outcome Although Joseon Korea expelled the Japanese and remains independent, Korea itself is more devastated by the war than any other in its history. The roots of anti-Japanese sentiment in Korea are found in this war.
In 1590 Japanese daimyo and general Toyotomi Hideyoshi established himself as the power behind the throne control- ling the entire nation. Toyotomi dreamed of making Japan the dominant power in East Asia and set the ambitious goal of conquering Ming dynasty China. Such an effort would have the advantage of diverting the energies of the ever-ambitious Japanese warlords from domestic affairs. To get at China, Toyotomi planned to first invade and secure Joseon (Choson) Korea, then a tributary state of China. Joseon Korea appeared weak and vulnerable to invasion. Having enjoyed two centuries of peace, its leaders had allowed the nation’s military to deteriorate. The Korean military forces were small, disorganized, poorly equipped, and scattered around the country.
When the Koreans refused a Japanese demand for free passage to China, which would have meant Japanese occupation of their country, Toyotomi dispatched forces across Tsushima Strait (Korea Strait). The resulting first invasion is known in Korea as the Japanese Disturbance of Imjin (1592 being an imjin year in the Chinese sexagenary cycle).
On May 23, 1592, Japanese ships carrying some 158,000 men crossed from Tsu- shima, easily brushed aside two Korean naval squadrons and landed at the port of Busan (Pusan) in southern Korea. The Japanese had the advantage of unity of command and superior weaponry in the form of matchlock firearms. Although the Koreans resisted the invasion, the Japanese soon secured Busan and, once they had reorganized, sent three columns northward. These met little resistance. In a major battle at Chungju (Ch’ungju) on June 7, the Japanese soundly defeated Korean Army forces under General Sin Nip. Several days later Korean king Sonjo fled north, first to Pyongyang, and then to Uiju on the Chinese border. Japanese forces entered the Korean capital of Seoul on June 9, only to discover much of the city burned and empty of inhabitants.
The Japanese expeditionary force then split into two main bodies: one under General Konishi Yukinaga proceeded north through western Korea to Pyongyang, while the other under General Kato Kiyomasa advanced up the eastern coast of Korea. Everywhere the Korean people paid a heavy price, with the Japanese killing many civilians as well as soldiers. (The Japanese kept a body count by routinely cutting off the ears of those slain.)
The Japanese military strategy called for the army to hold the southeastern and central regions of Korea, with the navy responsible for securing the rich rice- producing areas of Cholla (Chollq) and Chungcheong (Ch’ungch’ong) Provinces in order to secure a stable food supply for the occupying Japanese forces. This plan, however, rested on Japan maintaining control of the sea, also necessary in securing the lines of communication back to Japan, and that now came into question.
Korean admiral Yi Sun Sin (Yi Sun-sin), certainly one of history’s most brilliant naval commanders, was one of the few Korean leaders to have taken meaningful steps to prepare for a Japanese invasion. On March 9, 1591, with the threat of Japanese invasion fully apparent, Yi had been appointed head of the left naval command of Cholla Province, along the southeastern coast. He then designed and caused to be built the famed kobukson (turtle ship), a new type of warship and in fact the world’s first armored [note] warship.
Sufficiently detailed descriptions of these vessels survive to provide a fairly complete picture of their appearance. They were about 116 feet in length and 28 feet in beam. They had a raft-like rectangular-shaped hull, a transom bow and stern, and a superstructure supporting two masts, each with a square rectangular mat sail. A carved wooden dragon head was set at the bow.
The ships were powered by both sail and oar, with openings for 8-10 oars on each side of the superstructure. The oars were to provide additional speed and maneuverability. The superstructure was protected by a curved iron plated top that gave the vessel a turtle shell-like appearance. The iron plating had spikes set in it to prevent an enemy crew from boarding. The turtle ships mounted cannon: six on each side and several at the bow and stern.
The first of the turtle ships was launched just days before the Japanese invasion in May 1592. With the invasion, Yi collected 85 ships. These included two dozen galley battleships and 15 scout ships, with the remainder being fishing boat conversions. With this force, on June 16, 1592, Yi surprised and destroyed 26 Japanese ships off Okpo (Okp’o). The next day he sank another 16 Japanese ships off Chokjinpo (Chokjinp’o).
Following repairs, Yi sailed with 26 ships, including 2 turtle ships, and destroyed 12 more Japanese ships off Sacheon (Sach’on) on July 8. On July 10 he sank 20 other Japanese ships off Dangpo (Tangp’o). Reinforced, on July 13 he sank the majority of 26 Japanese ships at Dan- ghangpo (Tanghangp’o). These victories led the Japanese to send naval reinforcements. Yi, now with 55 ships, on August 13 discovered 75 Japanese ships at Kyonnaeryang (Kyonnaeryang) and sent a few of his own ships into the harbor in a successful effort to lure out the Japanese. The next day he captured 12 large Japanese ships and sank more than 40 others off Hanson Island (Hansan-do) in what is regarded as one of the most important Korean victories of the war. On August 16 he destroyed 30 or more of 40 Japanese ships at Angolpo (Angolp’o).
In September, Yi had at his disposal a fleet of 74 war galleys and 92 smaller vessels. He trained his men for three weeks and then set out for the principal Japanese base at Busan. Here the Japanese had 500 ships, 100 of them warships. On October 5 in the Battle of Busan, Yi attacked, destroying or capturing 100 Japanese vessels. He then scattered a large Japanese reinforcing convoy, sinking many of its ships.
The Japanese were now experiencing great difficulty ashore as well. Not only had Admiral Yi cut them off from resupply from Japan, but there was also a famine in Korea that reduced Japanese foraging, and the Japanese were under constant harassment from the increasing numbers of Koreans who joined insurgent militia forces known as uibyong (righteous warriors). Meanwhile, at the request of the vassal state of Korea, China intervened. In January 1593 Ming emperor Wanli (Zhu Yijun) sent a 40,000-man army commanded by General Li Rusonh into northern Korea, and on February 8 Chinese and Korean forces recaptured Pyongyang and pushed the Japanese forces southward. Chinese and Korean forces then prepared for a joint effort to retake Seoul. After they sustained heavy losses in a battle at Byeokjegwan (Pyokchegwan), however, the Chinese withdrew back to Pyongyang. This left the Korean forces vulnerable to an attack on their mountain fortifications north of the Han River at Haengju. Some 43,000 Japanese attacked, but after nine separate assaults and substantial casualties, the Japanese retreated southward. The Battle of Haengju of March 14, 1593, is celebrated in Korean history as one of the most important of the war.
With the principal Japanese generals, including Konishi Yukinaga, urging peace and the Chinese eager to return home, the two sides entered into talks. Japanese troops then withdrew from Seoul into an enclave around Pusan. The Japanese were determined, however, to secure the strong- hold of Jinju (Chinji), which controlled access to the key rice-producing area of Cholla Province. Already in November 1592 a far smaller Korean force led by Kim Si-min had defeated a much larger Japanese army there, inflicting 30,000 casualties. Now in July 1593, the Japanese sent 79,000 men against Jinju and this time captured it on July 27, slaughtering many of its inhabitants.
Truce talks between China and Japan opened in April 1593 and went on for three years without resolution, with each side refusing to accept the demands of the other. Meanwhile, the Japanese withdrew most of their troops from Korea, and the Chinese removed all of theirs. On April 23, 1594, Yi attacked and sank 31 Japanese ships in actions around Danghangpo. On March 1, 1597, General Toyotomi launched a new invasion from Japan, sending some 141,000 men by ship across the straits. Landing near Pusan, the Japanese forces again drove north, devastating much of the country and causing Ming China to again intervene militarily. The Koreans had been able to rebuild and improve their military, and this time the Japanese en- joyed less success on land and were held largely to Kyongsang Province.
The Japanese did, however, send out false information in an attempt to lure Admiral Yi into a trap. Aware of what the Japanese intended, Yi refused a royal order to attack, whereupon he was dismissed from command. His successor, Won Kyun, led the Korean fleet to destruction off Pusan in the Battle of Chilcheollyang (Ch’ilch’onnyang) on August 28, 1597. Won was among those killed, and the Koreans lost 157 of their 169 ships.
Following the disastrous Battle of Chilcheollyang, Yi was reinstated in command of the Korean Navy, now reduced to only 12 ships. Following a series of small victories, on December 4, 1597, in the Battle of Myeongnyang (Myongnyang), Yi employed his considerable experience and knowledge of Korean tides and currents to win his most brilliant victory over the Japanese. With only 12 ships of his own, he engaged 133 Japanese ships, although many of the latter were transport vessels. Yi sank 31 Japanese ships for no losses of his own before the remaining Japanese ships hauled off.
A lull in fighting of more than a year followed, giving Yi time to build up his naval strength. With some 150 ships, including 63 Ming warships led by Admiral Chen Lin, Yi attacked a Japanese fleet of equal size commanded by General Konishi Yukinaga. In the Battle of Noryang Strait of December 16, 1598, the Korean and Ming fleets captured or destroyed 200 Japanese ships. During the battle, however, Yi was struck and killed by a cannonball.
Again the Koreans and Chinese controlled the straits, and Japanese lines of communication to Korea were again effectively severed, cutting off their forces in Korea. Another motivation for peace was the death of Japanese general Toyotomi, the prime mover behind the invasion, on September 18, 1598. The new governing body of Japan, the Council of Five Elders, ordered the Japanese troops to evacuate Korea.
For Korea, the Japanese invasions were more devastating than any other war in their history including the 1950-1953 Korean War. The Koreans suffered tremendously from the Japanese presence but also at the hands of their allies, the Chinese. The decrease in the population had a tremendous effect on the agricultural economy, and the years that followed saw widespread famine, disease, and political upheaval. Certainly the Joseon dynasty never quite recovered from the shock of the war.
Korea also lost many priceless cultural treasures taken by the Japanese to Japan and never returned. The Japanese also took back to Japan tens of thousands of Koreans, most of them artisans and craftsmen, including highly skilled potters. (Korean pottery was then being highly prized and their work became the basis for much of subsequent Japanese pottery.) The departure of these skilled workers was a major blow to the Korean economy and greatly benefited that of Japan. Although some 7,000 Koreans were returned by Japan following the normalization of relations be- tween the two countries in 1607, a large portion of the remaining captives were sold to European traders-mostly Portuguese-who then resold them in Southeast Asia. It is no wonder that Korean nationalists cited the war and its heroes in seeking to rally resistance to the Japanese occupation of 1910-1945. Certainly much of the present anti-Japanese sentiment in Korea stems from the Japanese-Korean War of 1592-1598.
In China, the war of 1592-1598 was used to fuel nationalistic fervor during the Japanese invasions of China in the 20th century. The war is also often cited by Chinese historians as proof of Chinese- Korean friendship.
The war also brought political upheaval in Japan and ultimately resulted in arguably its most important battle. Following the death of Toyotomi in 1598, a struggle ensued between his most powerful vassals for control, Toyotomi’s son Hideyori then being only five years old. The leading nobles soon declared their allegiance to one side or the other, and on October 20, 1600, battle was joined at Sekigahara in what was probably both the largest and most important military engagement in Japanese history. Although fighting continued for some time thereafter, the victor at Sekigahara, Tokugawa Ieyasu, won out. Named shogun by Emperor Go-Yozei in 1603, Tokugawa moved the capital from Kyoto to Edo (Tokyo) and became de facto dictator of Japan. The Tokugawa shogunate lasted until the Meiji Restoration of 1868.
The war also had profound geopolitical significance in East Asia, as it weakened the Ming garrisons in Manchuria, making it far easier for the Manchus to attack there and ultimately bringing the military defeat of the Ming dynasty and the beginning of the Manchu dynasty.
[note] Samuel Hawley, The Imjin War: Japan’s Sixteenth-Century Invasion of Korea and Attempt to Conquer China, Berkeley: The Royal Asiatic Society and The Institute of East Asian Studies, University of California, Berkeley, 2005, 195–8, disputes the notion that the turtle boats were covered with metal plates.
Further Reading Brown, Delmer M. “The Impact of Firearms on Japanese Warfare, 1543-1598.” Far Eastern Quarterly 7(3) (May 1948): 236-253. Galuppini, Gino. Warships of the World: An Il- lustrated Encyclopedia. New York: Military Press, 1989. Hawley, Samuel. The Imjin War. London: Institute of East Asian Studies and the Royal Asiatic Society, Korea Branch, 2005. Henthorne, William E. A History of Korea. New York: Free Press, 1971. Kang, Ch’ol-won. Songung Yi Sun-sin [Yi- Sun-sin, a National Hero]. Seoul: Chisong Munhwa-sa, 1978. Kim, Jinwung. A History of Korea: From “Land of the Morning Calm” to States in Conflict. Bloomington: Indiana University Press, 2012. Park, Son-sik. Yi Sun-sin. Seoul: Kyujanggak, 1998. Sansom, George. A History of Japan, 1334- 1615. Stanford, CA: Stanford University Press, 1961. Swope, Kenneth M. “Crouching Tigers, Secret Weapons: Military Technology Employed during the Sino-Japanese-Korean War, 1592-1598.” Journal of Military History 69 (January 2005): 11-42. Swope, Kenneth M. A Dragon’s Head and a Serpent’s Tail: Ming China and the First Great East Asian War, 1592-1598. Norman: University of Oklahoma Press, 2009. Turnbull, Stephen R. Fighting Ships of the Far East (2): Japan and Korea, 612-1639. Buffalo, MN: Osprey, 2003. Turnbull, Stephen R. Samurai Invasion: Ja- pan’s Korean War, 1592-98. London: Cas- sell, 2002. Yi, Sun-sin. Nanjung Ilgi: War Diary of Admiral Yi Sun-sin. Edited by Sohn Pow-key and translated by Ha Tae-hung. Seoul: Yonsei University Press, 1977.