Hideyoshi Toyotomi, one of Japan's most famous shogun, launched two unsuccessful invasions of Korea — in 1592 and 1597. Before they were driven out, Hideyoshi's armies killed 100,000 Koreans. A mound near Kyoto known as Mimizuka contains the chopped-off noses of hundreds (maybe thousands) of Koreans killed in the campaign. The seven year Imjin War between 1592 and 1598 was East Asia’s largest ever engagement of troops. The war was a drawn out series of battles that saw the Japanese overwhelm Chosun defenses from Busan to Pyongyang until Ming Chinese forces came to help Korea.

The major Japanese invasions and warfare between 1592 and 1598 brought widespread devastation to the Korean peninsula. The war was characterized by repeated naval battles as the Japanese sought to reinforce and supply their troops. Korea’s call the war the Seven-Year War. A notable achievement in warfare occurred during this period when Admiral Yi Sun-shin and his fleet of ironclad “turtle boats” defeated Japanese naval forces.

In 1592, Hideyoshi invaded Korea — which had strong ties with Ming-Era China — for the first time. His armies quickly overran the peninsula before losing momentum in the face of a combined Korean-Chinese force. During peace talks, Hideyoshi demanded a division of Korea, freetrade status, and a Chinese princess as consort for the emperor. The equality with China sought by Japan was rebuffed by the Chinese, and peace efforts ended. In 1597 a second invasion was begun, but it abruptly ended with Hideyoshi's death in 1598.

Hideyoshi and Invasion of Korea

Hideyoshi Toyotomi is regarded as the George Washington and Napoleon of Japan. There are literally hundreds of books and comic books about him and one television mini-series about his life lasted an entire year. "No single person did more than Hideyoshi to shape the Japan of modern times," wrote Japan scholar and U.S. ambassador Edwin O. Reischauer.

A commoner by birth and without a surname, Hideyoshi was adopted by the Fujiwara family, given the surname Toyotomi, and granted the title kanpaku, representing civil and military control of all Japan. After more than a century of civil war and unrest, Hideyoshi restored order and unified all of Japan in 1590, after a famous battle at the Ara River in Yorii, involving 50,000 armed soldiers and the siege of hachigata castle. He helped establish Japan's "brilliant and efficient social order that seemed to master anything to which it applied its collective will." In Japan, he famously cracked down on Christians, threw missionaries out of the country, collected swords and guns from ordinary citizens so they couldn’t present a threat and took actions that helped to cut Japan off from the outside world until the mid 19th century.

It is said Hideyoshi's major ambition was to conquer China but to reach it he had to pass through Korea first. Some scholars say the main purpose of the invasion was to give Hideyoshi’s huge armies something to do after they had successfully unified Japan. According to “Topics in Japanese Cultural History”: “Historians sometimes debate Hideyoshi's motivation for the invasion. Some, for example, say the primary reason was to find an outlet for the energies of the many warriors in Japan, whose restlessness might have caused trouble at home. Others point out that Hideyoshi had even made plans for the conquest of India. Therefore, his own personal megalomania was the primary motivating force. [Source: “Topics in Japanese Cultural History” by Gregory Smits, Penn State University figal-sensei.org

Japanese Invasion of Korea in 1592

In 1592, an invasion force of approximately 170,000 men in 700 ships under Hideyoshi landed in Korea with the intent of using Korea as a stepping stone for the conquest of China. His forces were armed with guns, a weapon that was unknown in Korea. The early stages of the invasion went smoothly for the Japanese. The Japanese army landed at Pusan in March and controlled most of the Korean Peninsula by July. Seoul was captured, the royal family fled north, the slave population of Seoul revolted and burned most of the royal palace, and there were even reports that Japanese had lopped off the tops of the Seoul's most sacred energy-giving mountains. In the 1590s, Kyongbok — meaning "Palace of Grand Felicitation" — was a labyrinth of over 500 buildings. During a Japanese invasion in 1592 most of the buildings were burnt down — not by the Japanese but by Korean serfs who wished to destroy the official records of their servitude.

According to Haps: On the morning of May 23rd, 1592, at the order of Hideyoshi, around 160,000 troops set sail from Tsushima, Japan aboard hundreds of ships, for the port of Busan. Hideyoshi’s primary objective was the crown of Ming Dynasty China. Rebuffed on numerous diplomatic petitions for passage across Korea (a ludicrous inquiry) the Japanese general and “great unifier” of Japan, took the less attractive choice to subdue the peninsula before continuing west. It was a product of strategic calculation, with Korea as the logistical linchpin. Hideyoshi could not conquer so great a power as China, so far from home, without a reliable chain of supplies to feed the war machine as it marched, galloped and rolled towards the Chinese Crown. [Source: Haps, April 26, 2016]

According to “Topics in Japanese Cultural History”: “ Some members of the Korean court had warned the king and officials about the possibility of a Japanese invasion. But these warnings went unheeded, and the Korean side was unprepared. The seasoned warriors in Japan's army won victory after victory and soon overran the Korean capital. The Japanese forces continued northward toward China, but before they could enter China, a hastily-assembled Ming army engaged them in battle. From Ming China's point of view, it was better to fight Japan in Korea than in China. This Ming army stopped the Japanese advance but did not decisively defeat the Japanese army."~*

Japanese Invasion of Busan and the March to Seoul

According to Haps: “Once again, Busan would serve as the launching point for the squaring off of China and Japan. Three-hundred years earlier the machine was going the opposite direction with China twice invading Fukuoka under the orders of Yuan Dynasty China’s Kublai Khan. The first attempt, in 1274, failed. As did the second in 1281. Incredibly, both thwarted by typhoons, which the Japanese soon dubbed the “Divine Wind” or, as spoken in the native tongue, “Kamikaze.” [Source: Haps, April 26, 2016]

“Following a day-long journey at sea, Japanese troops stormed the beaches of Busan just after sundown, heading for the two primary fortresses in Dongnae. Armed with Portuguese firearm technology and battle-hardened by years of civil war at home, the Japanese troops, many of whom were Samurai, quickly routed the bow and arrow-wielding Busan forces. One reason why local defenses folded so easily was strategically inept Chosun policy which forbade local commanders from engaging a foreign invasion force until a court-appointed general could arrive from Seoul with royal troops. This policy additionally prevented cities around Busan from coming to her aid without royal consent. Interestingly, firearm technology had been presented to the Chosun court years earlier, but was mistakenly deemed an unnecessary tool for the art of war.”

The Chosun court responded to the invasion by fleeing to the Yalu River, an action that infuriated ordinary Koreans and led slaves to revolt and burn the registries. “Paekcheong (Those of the lowest social rank serving on the lands of feudal lords) viewed the Japanese as liberators from the harsh feudal system and capitalized on the loss of domestic security by setting fire to royal dwellings and government buildingsâincluding those where status ledgers for Korean slaves were held. It would take three months before Hideyoshi controlled much of the peninsula. As in most wars, civilians suffer the greatest; especially those in the vicarious position of living along the supply line from Busan to Pyongyang. It was here that Japanese troops used ‘scorched earth’ tactics which seeks to destroy everything in its path.

Stalemate Between Japan, China and Korea

King Sonjo requested military assistance from Beijing and, as the Chinese and Korean armies gradually pushed the Japanese south, the Korean navy frustrated Japanese efforts to initiate new attacks on the Korean Peninsula. With China’s control over over Chosun Dynasty Korea at stake, and the Japanese moving towards their capital, over 100,000 Ming Dynasty troops joined nearly 200,000 Koreans with Ming taking complete operational command. Kenneth Swope wrote in the Sungkyun Journal of East Asian Studies, Korean rulers of the era had little say as to how their fate would play out between the two warring powers. “At this point in 1593, the war entered a stalemate during which intrigues and negotiations failed to produce a settlement. As the suzerain of Chosun Korea, Ming China exercised tight control over the Koreans during the war. At the same time, Ming China negotiated bilaterally with Japan while often ignoring the wishes of the Korean government.” [Source: Haps, April 26, 2016]

According to “Topics in Japanese Cultural History”: ““After the initial Japanese victories, the war settled into a stalemate. Japanese forces held the major Korean cities. The were unable, however, to advance into China and came under constant harassment in outlying areas from bands of Korean and Chinese soldiers. [Source: “Topics in Japanese Cultural History” by Gregory Smits, Penn State University figal-sensei.org ~]

The war at sea went much worse for Japan. Korea was fortunate to have a brilliant admiral, Yi Sun-sin, whose forces kept constant pressure on Japanese supply lines. Admiral Yi created a radically new type of fighting ship: the world's first ironclad vessel. Called"turtle ships" because of their appearance, these low-profile, iron-plated ships were almost immune from enemy gunfire. They wreaked havoc on the Japanese navy.

“Hideyoshi eventually entered into negotiations with Ming China. The negotiations were a classic case of poor communication. The Ming emperor, misled by his officials who were reluctant to admit the extent of Japanese victories, was convinced that Hideyoshi was ready to surrender and become a vassal of Ming China. Hideyoshi, on the other hand, expected the Chinese side to be forthcoming with major concessions. When Hideyoshi finally discovered the truth, he exploded with rage and ordered a second invasion in 1597.

Admiral Lee and His Turtle Ships

Japanese forces marched through the peninsula at will until they were routed by General Yi Sun-sin and his fleet of armor-clad ships, the first of their kind. The Japanese fleets were destroyed wherever they were found, Japan's supply routes were cut, and facing Ming forces and so-called righteous armies that rose up to fight a guerrilla war (even Buddhist monks participated), the Japanese were forced to retreat to a narrow redoubt near Pusan.

Admiral Yi Sun-sin (1545-1598) is Korea’s most famous war hero and one of Korea's most important historical figure. Every Korean knows his story and his poetry and many schools in the country have a statue of him in their courtyard, but Westerner's sometimes confuse him with General Yi, the founder of the Chosun Dynasty. In a four month period in 1592, Admiral Yi turned the tide of a Japanese invasion by sinking almost 300 Japanese ships and cutting off Japanese supply and manpower links to Korea. He performed this feat with history's first iron clad ships — the so-called “turtle ships.”. Admiral Yi and his turtle ships helped change the balance of power in East Asia, by helping Korea shed its “shrimp between two whales” role and standing up to at least one whale, Japan (China was the other).

The small Korean navy under Admiral Yi Sun-sin used ironclad battleships known — because of their appearance — as turtle boats to make frequent attacks on the Japanese fleet attempting to resupply Japanese forces in Korea. Known as turtle boats, because the were shaped like turtles and turtle means long life, the Korean iron-clad ships were not really iron clad ships like the Monitor and Merrimack or as we know them. They were encased in thick plating with cannons sticking out at every point on their oval shape, propelled by oars and covered with metal spikes mainly to repel boarders. On the bow was a dragon’s head, which emitted a vile-smelling smoke, produced by burning sulphur and acid and was intended to spook the enemy not poison hem. The oars went through the bottom, instead if the sides, an innovation that kept the vessels from braking up during collisions. Sailors pumped up and down on the oars to maneuver the boat. A drummer pounded out a rhythm for the oarsmen to follow.

The Nanjung Ilgi — the War Diary of Admiral Yi Sun-sin — was placed on the UNESCO Memory of World Register in 2013. The Nanjung Ilgi is the handwritten war diary of Admiral Yi Sun-sin, The entire series narrates events that took place during a period of war, in addition to the admiral’s personal observations and commentary about the time and its controversial circumstances, which is considered to be a highly treasured description to Korean history. The diary consists of seven volumes of notes written almost daily from January 1592 through November 1598, just days before Yi was killed in the last sea battle of the war. The diary also contains a number of poems, recited by Koreans even to this day, heightening its literary value, of which is hardly found in other historical remains. War tactics and detailed strategies using the famous Geobukseon (Turtle Ship) designed by the admiral himself were also found here, attracting much attention from researchers. [Source: Korea Tourism Organization visitkorea.or.kr ]

According to UNESCO: Handwritten journal of Admiral Yi Sun-sin, written during the Japanese invasions of 1592-1598. It consists of seven volumes of notes written almost daily from January 1592 through November 1598, until the days before Yi Sun-si was killed on the cusp of a decisive victory, in the last sea battle of the war. The diary is without equal in world history as a commander's battlefield accounts. Written as a personal journal, it describes in detail the daily combat situations, the admiral's personal views and feelings, observations on the weather, topographical features of battlefields and the lives of common people. The style is simple and elegant. This war diary has been widely used in modern Western countries as well as in Korea to study the sea battles during the seven-year war.

Japanese Invasion of Korea in 1592 and General Yi

Japan, following failed peace negotiations with the Ming Dynasty, invaded Korea for a second time in 1597. The second invasion force numbered about 140,000. The Japanese scored a number of important victories at first but were stalled by Korean and Ming forces

According to to Haps: Hampered by the heroic efforts of Korean Admiral Yi Sun-shin and his fleet, Japanese supply lines suffered heavily during the second campaign. With large numbers of Chinese troops pouring in from the north, and Korean guerilla warfare activity, the Japanese were forced to expand construction of fortresses across the southeastern part of peninsula in an effort to maintain what they had captured. Over the course of the war, a total of 35 castles were erected, either from scratch or from the remains of conquered Korean fortresses. See Below. [Source: Haps, April 26, 2016]

After Japan withdrew in 1592, the Korean imperial government responded by reducing the Korean navy to 12 ships and demoting Admiral Yi to a commander. On August 15, 1597, 12 turtle ships confronted a fleet of 133 Japanese vessels in the Yellow Sea near Mokpo and destroyed 31 of the Japanese warships. The Japanese invasion force outnumbered the Koreans 11 to 1. In the most important naval engagement in Korean history, Admiral Yi used his famous iron-clad turtle ships to maneuver a retreating fleet of 500 Japanese vessels into a narrow funnel-shaped strait where he had previously submerged a giant chain. At the right time Yi ordered the chain to be lifted and the Japanese ships, pulled by a strong current, capsized one after another. Some 133 ships went down and the invasion was foiled. Yi was killed a year later by a stray bullet. His last words were, “The battle is urgent now. Don’t let the men know I’m dying.”

Japanese Castles in Korea

Haps reports: According to Stephen Turnbull in his book Japanese Castles in Korea 1592-1598, Hideyoshi saw the castles, known as waja in Japanese and waeseong in Korean, as a last ditch effort to maintain the Japanese presence on the peninsula. The waja line was essentially a response to the Chinese advance, and provided the last refuge for the occupying troops, writes Turnbull. The new fortresses may have had roles concerned with communications and harbour defence, but the principle underlying their creation was that of providing a final toehold on the Korean Peninsula. [Source: Haps, April 26, 2016]

Of the 35 castles constructed by Japanese forces, little more than fragments remain of most. A great place to get an idea of the structures that once straddled the Korean coastal area is the Gijang Cultural Center just outside of Busan. There you can see a model of the Imrang Fortress, which stood on the eastern coast as the northernmost Japanese defensive post in what were a series of ten castles east of the Nakdong River in the Busan area.

The castles built in Korea were similar to the Japanese mainland style of the 16th and 17th century, with towering stone walls and a command tower perched on top. The Imrang Fortress was erected on a hill overlooking the beach and it included a lower residence area around the port, though little of that remains today. Much like the Imrang Fortress, there are still bits and pieces of these 16th century strongholds out there for those curious to witness a page out of the Korean peninsula’s past. To see the most well-preserved castle, head further north to Ulsan for a tour of Seosaengpo. Built by Japanese General Kato Kiyomasa in 1592-1593 during the initial stages of the Imjin War, many of the original walls still remain intact.

For more on Japanese castles in Korea, including an excellent interactive map, check out wajo.japanese-castle-explorer.com or japanese-castle-explorer.com. You can also see more photos of Japanese castle remnants on Jens Walter’s German language blog at osnabrueck.wordpress.com.

Hideyoshi’s Death and the End of the Japanese Invasion of Korea in 1598

The war dragged on until Hideyoshi’s death in 1598. It ended then because the Japanese lost the will and reason for fighting and returned home. According to “Topics in Japanese Cultural History”: “Hideyoshi died in 1598 before the final outcome could be settled decisively. At this point, the major daimyo met in a council. None were enthusiastic about continuing the war, and they ordered the withdrawal the entire Japanese force. The war ended after years of bloodshed and devastation with nothing positive accomplished by any of the parties involved. The only possible exception was that Korean prisoners of war introduced a number of new cultural forms to Japan, particularly in the area of pottery." [Source: “Topics in Japanese Cultural History” by Gregory Smits, Penn State University figal-sensei.org ~]

On his deathbed in 1598, Toyotomi Hideyoshi was determined that his family stay in power. He made each of the most powerful leaders of the country swear allegiance to his 5-year-old son, Hideyori. According to “Topics in Japanese Cultural History”: “There is good evidence that Hideyoshi had become mentally unstable toward the end of his life. He certainly became more murderous (and he had a macabre interest in ears). Unable to produce a male child of his own, he eventually adopted a son and heir. Late in his life, one of Hideyoshi's wives unexpectedly gave birth to a healthy boy. Now with a biological son of his own, Hideyoshi ordered his adopted son to kill himself.” [Source: “Topics in Japanese Cultural History” by Gregory Smits, Penn State University figal-sensei.org ~]

In spite of the victory, the peninsula had been devastated. Refugees wandered its length, famine and disease were rampant, and even basic land relationships had been overturned by widespread destruction of registers. Although Japan's first attempts to subjugate Korea were unsuccessful, many of the central organizations of the Korean imperial military system were weakened by the impact of the invasion.

After the Japanese withdrew for good from Korea they left behind a country in ruins. According to 1598 “Song of Great Peace”:
“Higher than mountains, the bones
pile up in the field
Vast cities, great towns
become the burrows of wolves and foxes."

Manchu Invasion and the Hermit Kingdom

Although the Japanese were driven out of Korea by combined Korea and Ming forces and Chosun began to recover, a new emerging force — the Manchu — invaded both Korea and China. The impact of the overthrow of the Ming dynasty in China by the Manchus in 1644 one historian said "was comparable to that experienced by the Christian world after the loss of the Holy Land to the Muslim world." The Manchu established a new dynasty in China — the Qing (1644–1911) — and established tributary relations with Chosun.

Korea had barely recovered when the Manchus invaded from the north, fighting on all fronts to oust the Ming Dynasty. Invasions in 1627 and 1636 established tributary relations between Korea and the Manchu's Qing Dynasty (1644-1911). The invasions, however, were less destructive than the Japanese invasions, except in the northwest where Manchu forces wreaked havoc. Thereafter, the dynasty had a period of revival that, had it continued, might have left Korea much better prepared for its encounter with the West.

Drained and impoverished by violent invasions from China and Japan, Korea closed itself off from the outside world and became a "Hermit Kingdom" for the next 200 years. This was around the same time that China and Japan closed themselves off to the West. Chosun then experienced a long period of peace and became the center of Confucian thought..

In the seventeenth and eighteenth centuries, Korean rulers generally devoted little attention to the military, although King Injo (1623-49) did reorganize the army and establish five permanent military bases in the country. Military service became unpopular after the Japanese invasion. The yangban class no longer provided a large source of strong military leaders, and the lower classes generally preferred to pay a tax that exempted them from conscription. Because Korean rulers had little contact with the outside world, the Korean military establishment remained uninformed about developments of new weapons and modern battlefield tactics until the middle of the nineteenth century. [Source: Andrea Matles Savada and William Shaw, Library of Congress, 1990]

Image Sources: Wikimedia Commons.

Text Sources: South Korean government websites, Korea Tourism Organization, Cultural Heritage Administration, Republic of Korea, UNESCO, Wikipedia, Library of Congress, CIA World Factbook, World Bank, Lonely Planet guides, New York Times, Washington Post, Los Angeles Times, National Geographic, Smithsonian magazine, The New Yorker, “Culture and Customs of Korea” by Donald N. Clark, Chunghee Sarah Soh in “Countries and Their Cultures”, “Columbia Encyclopedia”, Korea Times, Korea Herald, The Hankyoreh, JoongAng Daily, Radio Free Asia, Bloomberg, Reuters, Associated Press, BBC, AFP, The Atlantic, Yomiuri Shimbun and various books and other publications.

Updated in July 2021

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