Japanese invasions of Korea (1592–98)

The Japanese invasions of Korea comprised two separate yet linked operations: an initial invasion of 1592, a brief ceasefire in 1596, and a second invasion in 1597. The conflict ended by 1598 in a military stalemate and the withdrawal of Japanese forces from the Korean peninsula.

The invasions were launched by Toyotomi Hideyoshi with the intent of conquering Joseon Dynasty Korea and Ming Dynasty China. Japan quickly succeeded in occupying the Korean Peninsula, but the numerical superiority of the combined Ming and Joseon armies eventually resulted in a withdrawal towards coastal areas and a military stalemate. With Hideyoshi's death in September 1598, the Japanese forces in Korea were ordered to withdraw back to Japan by the new governing Council of Five Elders. Final peace negotiations between the parties followed afterwards and continued for several years, ultimately resulting in the normalization of relations.

Name
In Korean, the first invasion (1592–1596) is literally called the "Japanese (倭 &#124;wae&#124;) Disturbance (亂 &#124;ran&#124;) of Imjin" (1592 being an imjin year in the sexagenary cycle). In Chinese, the wars are referred to as the "Wanli Korean Campaign", after then reigning Chinese emperor, or the "Renchen War to Defend the Nation" (壬辰衛國戰爭), where renchen (壬辰) is the Chinese reading of imjin. In Japanese, the war is called Bunroku no eki (Bunroku referring to the Japanese era under the Emperor Go-Yōzei, spanning the period from 1592 to 1596). The second invasion (1597–1598) is called the "Second War of Jeong-yu" and "Keichō no eki", respectively. In Japanese, the war was also called "Kara iri" (唐入り, literally "entry to China") in Edo period (17–19C) because Japan's ultimate purpose at the commencement of the invasion was the conquest of Ming China, although with the reality that the conflict was largely confined to the Korean Peninsula for the duration of the war, the armies of Toyotomi Hideyoshi would alter their immediate objectives throughout the campaign.

Overview
In 1592, with an army of approximately 158,000 troops, Toyotomi Hideyoshi launched what would end up being the first of two invasions of Korea, with the intent of conquering Joseon Korea and eventually Ming Dynasty China. Initially, the Japanese forces saw overwhelming success on land, capturing both Seoul and Pyongyang, and completing the occupation of most of the Korean Peninsula in three months. This success on land, however, was tempered by defeats at sea, where the Korean navy would continue to harass the Japanese supply fleets. These trends, with some exceptions on both sides, held true throughout much of the conflict. The Japanese forces, well trained, confident, and experienced after the numerous battles and conflicts of the Sengoku Period, typically held the field in most land engagements, but were eventually hampered in their advances as their communication and supply lines were disrupted.

Ming China quickly interpreted the Japanese invasions as a challenge and threat to its tributary system and with the request of Korea, their entry into the conflict under the Wanli Emperor, and their extensive land forces, brought about an eventual military stalemate. The war stalled for five years during which Japan and Ming China attempted to negotiate a peaceful compromise. The first phase of the invasion lasted from 1592 until 1596, with a brief interlude for what would be failed peace negotiations between 1596 and 1597.

In 1597, Japan renewed its offensive by invading Korea a second time. The pattern of the second invasion largely mirrored that of the first. With Hideyoshi's death in September 1598, limited progress on land (with most Japanese forces garrisoned in coastal fortresses in the south), and continued lack of security at sea, the remaining Japanese forces in Korea were ordered to withdraw back to Japan. Final peace negotiations between the parties followed afterwards and continued for several years, ultimately resulting in the normalization of relations.

Effects
Korea lost a large portion of its military strength and faced enormous financial difficulties as a result of the war taking place almost entirely on its soil. It also lost a large portion of its civilian population to both warfare and famine.

In addition to the human losses, Korea suffered tremendous cultural, economic, and infrastructural damage, including a large reduction in the amount of arable land, the destruction and confiscation of significant artworks, artifacts, and historical documents, and the loss of artisans and technicians. During this time, the main Korean royal palaces Gyeongbokgung, Changdeokgung, and Changgyeonggung were all burned down by Korean natives, and Deoksugung was used as a temporary palace. In many instances, the destruction of palaces and government offices was a result of class conflicts and internal divisions as much as the invasion itself. The Baekjeong (Korean natives of the lowest social rank) often welcomed the Japanese army as liberation forces, and taking advantage of the lack of internal security brought on by invasion, would set fire to changnye (Korean government offices) in which status ledgers for Korean slaves had been kept.

The heavy financial burden placed on China by this war, as well as two other wars in the south, adversely affected its military capabilities and partly contributed to the eventual fall of the Ming Dynasty and the rise of the Qing Dynasty. However, the sinocentric tributary system that Ming had defended was maintained by the Qing, and ultimately, the war resulted in a maintenance of the status quo – with the re-establishment of trade and the normalization of relations between all three parties.

Korea and China before the war
In 1392, the Korean General Yi Seong-gye led a successful coup to take political power from King U of the Goryeo Dynasty by using military force. His followers forced Yi to take the crown, thus founding the Joseon Dynasty. In search of a justification for its rule given the lack of a royal bloodline, the new regime received recognition from China and integration into its tributary system within the context of the Mandate of Heaven. Within this tributary system, China assumed the role of a "big brother", with Korea maintaining a favored relationship among tributory states in return for accepting the subservient tributary role of a "younger brother". In 1402, Japan under Ashikaga Yoshimitsu was conferred the title of 'King of Japan' by the Emperor of Ming and through this title had similarly accepted a position in the tributary system as of 1404. This, however, it quickly renounced only a few years later under Ashikaga Yoshimochi in 1411, choosing, unlike Korea, to no longer be subject to oversight and control from Ming.

Unlike the situation over one thousand years earlier when Tang Dynasty China had an antagonistic relationship with Goguryeo, one of the Three Kingdoms of Korea, Ming China had close trading and diplomatic relations with the Korean Joseon Dynasty, which remained a tributary state, but also enjoyed continuous trade relations with Japan.

The two dynasties, Ming and Joseon (also called Choson), shared much in common: both emerged during the fourteenth century at the fall of Mongolian rule, embraced Confucian ideals in society, and faced similar external threats (the Jurchen raiders and the Wokou pirates). Internally, both China and Korea were troubled with fights among competing political factions, which would significantly influence decisions made by the Koreans prior to the war, and those made during the war by the Chinese. Dependence on each other for trade and also having common enemies resulted in Korea and Ming China having a friendly relationship.

The Wanli Emperor succeeded to the Ming dynasty in the year 1572 at the age of 9. For the first 10 years of his reign, the Ming was largely run by his teacher and guardian, Zhang Juzheng, who pushed through a series of reforms that revitalized the declining dynasty and made major breakthroughs in several of the key areas that had plagued the Ming, especially its financial problems. Zhang also made strong progress in defending against the Mongols of the north, and (as opposed to the corrupt practices of the past) promoted military generals based on their merits, such as Li Chengliang and Qi Jiguang.

After Zhang Juzheng's death in 1582, the Ming court slowly began to reverse some of his reforms and the Wanli Emperor himself increasingly became disillusioned and uninterested with daily politics. The Ming dynasty was in effect still at a relatively revitalized stage during the 1590s.

The Ming saw a string of conflicts during this period. Aside from their endless struggle against the Mongolians, they were also dealing with a military rebellion in Ningxia just before the war broke out, along with a border war with the Burmese Taungoo dynasty that coincided with the Imjin war. Their conflicts with the Wokou pirates a couple decades earlier also gave them significant experience against the Japanese style of warfare. Japan was by this time ending a period of internal conflict and the process of unification had been taken forward by Toyotomi. Japan launched their first attack on the Korean Peninsula, with the pretext that Korea refused to let Japanese soldiers pass through their land to militarily confront China. This could have effectively been true since Japan was eager, for social and economic reasons, to take land on the continent and expand.

Hideyoshi and his preparations
By the last decade of the 16th century, Hideyoshi as daimyō had unified all of Japan in a brief period of peace. Since Hideyoshi came to hold power in the absence of a legitimate Minamoto lineage successor necessary for the Imperial Shogun commission, he sought for military power to legitimize his rule and to decrease his dependence on the Imperial family. It is also suggested that Hideyoshi planned an invasion of China to fulfill the dreams of his late lord Oda Nobunaga, and to mitigate the possible threat of civil disorder or rebellion posed by the large number of now idle samurai and soldiers in unified Japan. However, it is also quite possible that Hideyoshi might have set a more realistic goal of subjugating the smaller neighbouring states (i.e. Ryukyus, Luzon, Taiwan, and Korea), and treating the larger or more distant countries as trading partners, as all throughout the invasion of Korea, Hideyoshi sought for legal tally trade with China Hideyoshi's need for military supremacy as a justification for his rule which lacked Shogunal background could, on an international level, eventually translate into an order with Japan's neighbouring countries below Japan. Hideyoshi was also tempted by an external conflict to prevent internal rebellion within Japan. This would keep his newly formed state united against a common enemy, and prevent the Daimyo from acting on any ambitions against his rule. Fighting a war away from Japanese territory would also prevent territorial destruction, and maintain the infrastructure of the state.. These considerations would be consistent with the fact that Hideyoshi was not a Shogun nor had any bonds with the royal bloodline.

The defeat of the Odawara-based Hōjō clan in 1590 finally brought about the second unification of Japan, and Hideyoshi began preparing for the next war. Beginning in March 1591, the Kyūshū daimyō and their labor forces constructed a castle at Nagoya (in modern-day Karatsu) (not to be confused with present day Nagoya city in Aichi prefecture) as the center for the mobilization of the invasion forces.

Hideyoshi planned for a possible war with Korea long before completing the unification of Japan, and made preparations on many fronts. As early 1578, Hideyoshi, then fighting under Oda Nobunaga against Mōri Terumoto for control of the Chūgoku region of Japan, informed Terumoto of Nobunaga's plan to conquer China. In 1592 Hideyoshi sent a letter to the Philippines demanding tribute from the governor general and stating that Japan had already received tribute from Korea (which was a misunderstanding, as explained below) and the Ryukyus.

As for the military preparations, the construction of as many as 2,000 ships may have begun as early as 1586. To estimate the strength of the Korean military, Hideyoshi sent an assault force of 26 ships to the southern coast of Korea in 1587. On the diplomatic front, Hideyoshi began to establish friendly relations with China long before completing the unification of Japan and helped to police the trade routes against the wakō.

Diplomatic dealings between Japan and Korea
In 1587, Hideyoshi sent his first envoy Yutani Yasuhiro, to Korea, which was during the rule of King Seonjo to re-establish diplomatic relations between Korea and Japan (broken since the Japanese pirate raid in 1555), which Hideyoshi hoped to use as a foundation to induce the Korean court to join Japan in a war against China. Yasuhiro, with his warrior background and an attitude disdainful of the Korean officials and their customs, failed to receive the promise of future ambassadorial missions from Korea.

Around May 1589, Hideyoshi's second embassy, consisting of Sō Yoshitoshi (or Yoshitomo), Yanagawa Shigenobu and Buddhist monk Genso reached Korea and secured the promise of a Korean embassy to Japan in exchange for a group of Korean rebels which had taken refuge in Japan.

In 1587, Hideyoshi had ordered the adopted father of Yoshitoshi and the daimyō of Tsushima, Sō Yoshishige, to offer the Joseon Dynasty an ultimatum of submitting to Japan and participating in the conquest of China, or facing the prospect of open war with Japan. However, as Tsushima enjoyed a special trading position as the single checkpoint to Korea for all Japanese ships and had permission from Korea to trade with as many as 50 of its own vessels, the Sō family had a vested interest in preventing conflict with Korea, and delayed the talks for nearly two years. Even when Hideyoshi renewed his order, Sō Yoshitoshi reduced the visit to the Korean court to a campaign to better relations between the two countries. Near the end of the ambassadorial mission, Yoshitoshi presented King Sŏnjo a brace of peafowl and matchlock guns - the first advanced fire-arms to come to Korea. Yu Seong-ryong, a high-ranking scholar official, suggested that the military put the arquebus into production and use, but the Korean court failed to appreciate its merits. This lack of interest and underestimation of the power of the arquebus guns greatly contributed to the failures of the Korean army early in the war.

On April 1590, the Korean ambassadors including Hwang Yun-gil, Kim Saung-il and others left for Kyoto, where they waited for two months while Hideyoshi was finishing his campaign against the Hōjō clan. Upon his return, they exchanged ceremonial gifts and delivered King Sŏnjo's letter to Hideyoshi. Hideyoshi assumed that the Koreans had come to pay a tributary homage to Japan, but the Koreans still refused. For this reason the ambassadors were not given the formal treatment that was due to diplomatic representatives. In the end, the Korean ambassadors asked for Hideyoshi to write a reply to Sŏnjo, for which they waited 20 days at the port of Sakai. The letter, redrafted as requested by the ambassadors on the ground that it was too discourteous, invited Korea to submit to Japan and join in a war against China. Upon the ambassadors' return, the Korean court held serious discussions concerning Japan's invitation; while Hwang Yun-gil reported to the Korean court conflicting estimates of Japanese military strength and intentions. They nonetheless pressed that a war was imminent. Kim Saung-il claimed that Hideyoshi's letter was nothing but a bluff. Moreover, the Korean court, aware only that Japan was in turmoil with various clan armies fighting each other, substantially underrated the combined strength and abilities of many Japanese armies at the time. Some, including King Sŏnjo, argued that Ming should be informed about the dealings with Japan, as failure to do so could make Ming suspect Korea's allegiance, but the Korean court finally concluded to wait further until the appropriate course of action became definite.

In the end, Hideyoshi's diplomatic negotiations did not produce the desired result with Korea. The Joseon Court approached Japan as a country inferior to Korea, and saw itself as superior according to its favored position within the Chinese tributary system. It mistakenly evaluated Hideyoshi's threats of invasions to be no better than the common wakō Japanese pirate raids. The Korean court handed to Shigenobu and Genso, Hideyoshi's third embassy, King Sŏnjo's letter rebuking Hideyoshi for challenging the Chinese tributary system. Hideyoshi replied with another letter, but since it was not presented by a diplomat in person as expected by custom, the Korean Court ignored it. After this denial of his second request, Hideyoshi proceeded to launch his armies against Korea in 1592.

Military capabilities


The two major security threats to Korea and China at the time were the Jurchens, who raided along the northern borders, and the wakō (Japanese pirates), who pillaged the coastal villages and trade ships.

This defensive stance within an environment of relative peace pushed the Koreans to depend on the strength of their fortresses and warships. With the transmission of gunpowder and firearms technology from the China during the Goryeo Dynasty, Korea improved upon the original Chinese designs of firearms (Zhen Tian Lei) and developed advanced cannon which were used with great efficiency at sea. Even though China was the main source of new military technologies in Asia, Korea was a manufacturing base of both cannon and shipbuilding during this era.

Japan, on the other hand, had been in a state of civil war for over a century, which had the result of turning Japan into a very proficient warlike society. When traders from Portugal arrived in Japan and introduced arquebuses and muskets, the Japanese warlords were quick to adapt to this innovative weapon, giving them a large advantage over the Korean armies. While Korean cannon were not adapted for effective use on land, and firearms were of a less advanced design, the small firearms carried by Japanese soldiers proved to be particularly effective during land engagements and sieges. This strategic difference in weapons development and implementation contributed to the trend during the war of Japanese dominance on land and Korean dominance at sea.

As Japan had been at war since the mid-15th century, Toyotomi Hideyoshi had half a million battle-hardened soldiers at his disposal to form a remarkable professional army in Asia for the invasion of Korea. While Japan's chaotic state had left the Koreans with a very low estimate of Japan as a military threat, a new sense of unity among the different political factions in Japan, the "Sword hunt" in 1588, (the confiscation of all weapons from the peasants) indicated otherwise. Along with the hunt came "The Separation Edict" in 1591, which effectively put an end to all Japanese wakō piracy by prohibiting the daimyōs to support the pirates within their fiefs. Ironically enough, the Koreans believed that Hideyoshi's invasion would be just an extension of the previous pirate raids that had been repelled before. As for the military situation in Joseon, the Korean scholar official Yu Seong-ryong observed, "not one in a hundred [Korean generals] knew the methods of drilling soldiers": rise in ranks depended far more on social connections than military knowledge. Korean soldiers were disorganized, ill-trained and ill-equipped, and they were used mostly in construction projects such as building castle walls.

Problems with Joseon Defense Policies
There were several defects with the organization of the Joseon-era Korean military defence system. An example was a defence policy that stated local officers could not individually respond to a foreign invasion outside of their jurisdiction until a higher ranking general, appointed by the king's court, arrived with a newly mobilized army. This arrangement was highly inefficient since the nearby forces would remain stationary until the mobile border commander arrived on the scene and took control. Secondly, as the appointed general often came from an outside region, he was likely to be unfamiliar with the natural environment, the available technology and manpower of the invaded region. Finally, as a main army was never maintained, new and ill-trained recruits conscripted during war constituted a significant part of the army. The Korean court managed to carry out some reforms, but they remain problematic. For example, the military training center established in 1589 in the Gyeongsang province recruited mostly either too young or too old soldiers (as able men targeted by the policy had higher priorities such as farming and other economic activities), augmented by some adventure-seeking aristocrats and slaves buying their freedom.

The dominant form of the Korean fortresses was the "Sanseong", or the mountain fortress, which consisted of a stone wall that continued around a mountain in a serpentine fashion. These walls were poorly designed with little use of towers and cross-fire positions (usually seen in European fortifications) and were mostly low in height. It was a wartime policy for everyone to evacuate to one of these nearby fortresses and for those who failed to do so to be assumed to be collaborators with the enemy; however, the policy never held any great effect because the fortresses were out of reach for most refugees.

Troop strength
Hideyoshi mobilized his army at the Nagoya Castle on Kyūshū (present-day Karatsu), newly built for the sole purpose of housing the invasion forces and the reserves. The first invasion consisted of nine divisions totaling 158,800 men, of which the last two of 21,500 were stationed as reserves in Tsushima and Iki respectively. The Japanese used a total of 500,000 troops throughout the entire war.

On the other hand, Joseon maintained only a few military units with no field army, and its defense depended heavily on the mobilization of the citizen soldiers in case of emergency. During the first invasion, Joseon deployed a total of 84,500 regular troops throughout, assisted by 22,000 non-regular volunteers. Ming troops never numbered more than 60,000 troops in Korea at any point of the war.

Weapons


Since its introduction by the Portuguese traders on the island of Tanegashima in 1543, the arquebus had become widely used in Japan. While both Korea and China had also been introduced to firearms similar to the Portuguese arquebus, most were older models. The Korean soldiers' small firearms was a handgun with simple mechanism either with gunstock or wooden shaft attached. When the Japanese diplomats presented the Korean court arquebuses as gifts, the Korean scholar-official Yu Seong-ryong advocated the use of the new weapon but the Korean court failed to realize its potency. In contrast, the Japanese often deployed the arquebus in combination with archery in war.

The Chinese used a variety of weapons, including long bows, swords, firearms, early kind of land mines and early hand grenades.

Chinese also demonstrated massive use of rocket-propelled arrows, notably during the Siege of Pyongyang in January 1593. During siege actions, Chinese deployed rattan shields and iron pavises (large shields), reputed to be musket-proof.

The Japanese defeated successive Korean armies with a combination of muskets, spears and swords. While muskets used by the Japanese were superior to Korean bows in terms of penetration, the former lacked the range, accuracy, and fire rate of the latter. Numerous battle accounts from the Annal of Joseon dynasty and various essays, diaries of Korean officials and commanders show that musket alone could not ensure victory. By employing both musket and arme blanche ("cold steel", swords, lances, spears, and the like), the Japanese were able to achieve success during the early phase of war. Indeed, the ferocious charge of Japanese troops with spears and swords were often more decisive than with muskets. This was because the Koreans were poorly trained in close combat, and lacked battlefield experience and discipline. Thus Korean soldiers were unable to hold their line against charging Japanese soldiers. The following words from a Korean military official named Shi-eon Lee to the Korean king clearly shows such weakness: The King asked him [Shi-eon Lee], "You have already told me about the low accuracy of Japanese muskets. Why, then, are Korean armies having great problem with defeating them?" [Shi-eon Lee] then answered, "The Korean soldiers cower before the enemy and flee for their lives even before they have engaged the enemy. As for the commanders, they seldom leave their positions because they fear that they might be executed for deserting. However, there is a limit to executing deserting soldiers since there are so many of them. Truly, the Japanese aren't good musketeers, but they advance so rapidly that they appear right in front of the Koreans in the time Koreans can shoot only two arrows. It is said that Koreans are good archers, but they seldom hit the targets when the enemy is too far away, and are too scared to shoot when the enemy is near because they fear Japanese swords. Archery often becomes useless because Koreans, fearing the Japanese arme blanche, can barely shoot. The Japanese are reputed to be good swordsmen, but it is possible for Koreans to draw swords and hold their ground. However, the Koreans seldom do this and merely run for their lives." As for field artillery, it seems the Koreans seldom employed them, with cannons mainly used in siege action and in defending castles. According to the "The Diary of a Militia" (향병일기; Hyangbyeong-ilgi), which is stored in the database of National Institute of Korean History, there are only very limited instances of Koreans employing artillery in the field, with largely ineffective results. The same sources also note that some irregular Korean units with government-supplied weapons used explosive shots fired from mortars at the open terrain, but this occurred more on an isolated one-off basis. The Chinese seem to have been more active in employing field artillery than the Koreans. One of the notable Chinese field guns was the "Great General Cannon". This was a large breech-loading cannon with a two-wheeled cart, shooting an iron ball weighing about 10 kilograms. The Japanese, on the other hand, employed field artillery only where strategically advantageous in both siege and field warfare situations, often using captured pieces were available.

The Koreans actively deployed their cavalry divisions in action, however they often suffered significant disadvantages. Terrain was often mountainous, which was not generally suitable for cavalry charges, the farmland tended to have many ditches, and it was often barren and lacked grass essential for feeding the horses. In addition, Japanese use of the arquebus at long range and in concentrated volleys negated any possibility of effective cavalry tactics. Korean cavalrymen's primary weapons were bows, with swords and lances holding only subsidiary positions. Most of cavalry action for the Koreans took place in the Battle of Chungju at the beginning of the war where they were outnumbered and wiped out by Japanese infantry. Although the Japanese divisions also fielded cavalry (they, however, dismounted when engaged in action, acting more like mounted infantry) and occasionally specialized firearms were used on horseback, though most cavalrymen preferred the conventional yari (spear), their use was reduced by increasing logistical difficulties and the increasing use of firearms by the Koreans and Chinese.

Naval power


In contrast to the Japanese advantages on land, Korea possessed a large advantage at sea. Advanced artillery and shipbuilding technology, along with an experienced naval history against Japanese pirates, allowed the Korean navy to field highly advanced and formidable watercraft. By the time of the Japanese invasion, Korea employed the panokseon, a powerful galley-type ship armed with cannon that outranged most Japanese vessels. The Korean Navy would use this naval superiority to disrupt the Japanese logistical network off the west coast of Korean Peninsula. This advantage, however, would not affect Japan's ability to continuously reinforce its armies through the supply route from Tsushima in Japan to Pusan in Korea, especially once Korean naval bases in the immediate area were neutralized by Japanese ground forces. The Korean navy led by Yi Sun-sin would withdraw and re-base in the northern border of Jeolla Province. While not able to entirely prevent reinforcement, the Korean navy would continue to harass and inflict losses on the Japanese supply fleets throughout the duration of the war.

As virtually all Japanese ships in the first phase of the war lacked cannon artillery, Korean ships outranged and bombarded Japanese ships with impunity outside the range of the Japanese muskets, arrows, and catapults. When the Japanese attempted to outfit cannon to their ships, their lightweight ship design prohibited using more than a few per vessel and usually lacked the firepower or range of their Korean counterparts In order to bolster their fleet, the Japanese considered attempting to employ two Portuguese galleons to join the invasion.

In addition to a lack of effective naval armament, most Japanese ships were modified merchant vessels more suited for transportation of troops and equipment than fielding artillery weapons. Most Japanese ships were also constructed with a deep keel and a single sail, that while provided speed limited movement to favourable winds and manouevrability was considerably disadvantaged by Korea's narrow coastal waters. Korean ships in contrast fielded multiple sails and crews providing oar power, and were constructed with a flat keel that enabled sharp turns. Additionally Japanese ships were constructed with iron nails while the Korean panokseons used wooden pegs. In water, nails corroded and loosened while wooden pegs expand and strengthened the joints.

Busan and Dadaejin
On May 23, 1592, the First Division of the Japanese invasion army consisting of 7,000 men led by Konishi Yukinaga left Tsushima in the morning, and arrived at the port city of Busan in the evening. Korean naval intelligence had detected the Japanese fleet, but Won Gyun, the Right Naval Commander of Gyeongsang, misidentified the fleet as trading vessels on a mission. A later report of the arrival of an additional 100 Japanese vessels raised his suspicions, but the general did nothing about it. Sō Yoshitoshi landed alone on the Busan shore to ask the Koreans for a safe passage to China for the last time; the Koreans refused, and Sō Yoshitoshi laid siege to the city while Konishi Yukinaga attacked the nearby fort of Dadaejin the next morning. Japanese accounts claim that the battles dealt the Koreans complete annihilation (one claims 8,500 deaths, and another, 30,000 heads), while a Korean account claims that the Japanese themselves took significant losses before sacking the city.

Dongrae


On the morning of May 25, 1592, the First Division arrived at Dongrae eupseong. The resulting fight lasted twelve hours, killed 3,000, and resulted in Japanese victory. (Siege of Dongnae)

Occupation of the Gyeongsang Province
Katō Kiyomasa's Second Division landed in Busan on May 27, and Kuroda Nagamasa's Third Division, west of Nakdong, on May 28. The Second Division took the abandoned city of Tongdo on May 28, and captured Kyongju on May 30. The Third Division, upon landing, captured the nearby Kimhae castle by keeping the defenders under pressure with gunfire while building ramps up to the walls with bundles of crops. By June 3, the Third Division captured Unsan, Changnyong, Hyonpung, and Songju. Meanwhile, Konishi Yukinaga's First Division passed the Yangsan mountain fortress (captured on the night of the Battle of Dongrae, when its defenders fled after the Japanese scouting parties fired their arquebuses), and captured the Miryang castle on the afternoon of May 26. The First Division secured the Cheongdo fortress in the next few days, and destroyed the city of Daegu. By June 3, the First Division crossed the Nakdong River, and stopped at the Sonsan mountain.

Joseon response
Upon receiving the news of the Japanese attacks, the Joseon government appointed General Yi Il as the mobile border commander, as was the established policy. General Yi headed to Myongyong near the beginning of the strategically important Choryong pass to gather troops, but he had to travel further south to meet the troops assembled at the city of Daegu. There, General Yi moved all troops back to Sangju, except for the survivors of the Battle of Dongrae who were to be stationed as a rearguard at the Choryong pass.

Battle of Sangju
On April 25, General Yi deployed a force of less than 1,000 men on two small hills to face the approaching First Division. Assuming that a rising smoke was from the burning of buildings by a nearby Japanese force, General Yi sent an officer to scout on horseback; however, as he neared a bridge, the officer was ambushed by Japanese musket fire from below the bridge, and was beheaded. The Korean troops, watching him fall, were greatly demoralized. Soon the Japanese began the battle with their arquebuses; the Koreans replied with their arrows, which fell short of their targets. The Japanese forces, having been divided into three, attacked the Korean lines from both the front and the two flanks; the battle ended with General Yi Il's retreat and 700 Korean casualties.

Battle of Chungju
General Yi Il then planned to use the Choryong pass, the only path through the western end of the Sobaek mountain range, to check the Japanese advance. However, another commander appointed by the Joseon government, Sin Rip, had arrived in the area with a cavalry division and moved 100,000 combined troops to the Chungju fortress located above the Choryong pass. Rather than face a siege, Sin Rip decided to fight a battle in the open fields of Tangeumdae, which he felt ideal for the deployment of his cavalry unit. Since the cavalry consisted mostly of new recruits, however, Sin Rip was concerned that his troops may easily be tempted to flee the battle. As a result, he felt the need to trap his forces in the triangular area formed by the convergence of the Talcheon and Han rivers in the shape of a "Y". This field, however, was dotted with flooded rice paddies and was generally not suitable for cavalry action.

On June 5, 1592 the First Division of approximately 18,000 men led by Konishi Yukinaga left Sangju and reached an abandoned fortress at Mungyong by night. The next day, the First Division arrived at Tangumdae in the early afternoon where they faced the Korean cavalry unit at the Battle of Chungju. Konishi divided his forces into three and attacked with arquebuses from both flanks as well as the front. The Korean arrows fell short of the Japanese troops, which were beyond their range, and General Sin's two charges failed to break the Japanese lines. General Sin then killed himself in the river, and the Koreans that tried to escape by the river either drowned or were decapitated by the pursuing Japanese.

Capture of Seoul
The Second Division led by Katō Kiyomasa arrived at Chungju, with the Third Division camped not far behind. There, Katō expressed his anger against Konishi for not waiting at Busan as planned, and attempting to take all of the glory for himself; Nabeshima Naoshige then proposed a compromise of dividing the Japanese troops into two separate groups to follow two different routes to Hanseong (the capital and present-day Seoul), and allowing Katō Kiyomasa to choose the route that the Second Division would take to reach Seoul. The two divisions began the race to capture Hanseong on June 8, and Katō took the shorter route across the Han River while Konishi went further upstream where smaller waters posed a lesser barrier. Konishi arrived at Hanseong first on June 10 while the Second Division was halted at the river with no boats with which to cross it. The First Division found the castle undefended with its gates tightly locked, as King Seonjo had fled the day before. The Japanese broke into a small floodgate, located in the castle wall, and opened the capital city's gate from within. Katō's Second Division arrived at the capital the next day (having taken the same route as the First Division), and the Third and Fourth Divisions the day after. Meanwhile, the Fifth, Sixth, Seventh, and Eighth Divisions had landed on Busan, with the Ninth Division kept in reserve on the island of Iki.

Parts of Hanseong had already been looted and torched, including bureaus holding the slave records and the weapons, and they were already abandoned by its inhabitants. General Kim Myong-won, in charge of the defenses along the Han River, had retreated. The King's subjects stole the animals in the royal stables and fled before him, leaving the King to rely on farm animals. In every village, the King's party was met by inhabitants, lined up by the road, grieving that their King was abandoning them, and neglecting their duty of paying homage. Parts of the southern shore of the Imjin River was burnt to deprive the Japanese troops of materials with which to make their crossing, and General Kim Myong-won deployed 12,000 troops at five points along the river.

Crossing of the Imjin River
While the First Division rested in Hanseong, the Second Division began heading north, only to be delayed by the Imjin River for two weeks. The Japanese sent a familiar message to the Koreans on the other shore requesting them to open way to China, but the Koreans rejected this. Afterwards, the Japanese commanders withdrew their main forces to the safety of the Paju fortress; the Koreans saw this as a retreat, and launched an attack at dawn against the remaining Japanese troops on the southern shore of the Imjin River. The main Japanese body retaliated against the isolated Korean troops, and acquired their boats; in response the Korean General Kim Myong-won retreated with his forces to the Kaesong fortress.

Distribution of Japanese forces in 1592
With the Kaesong castle having been sacked shortly after General Kim Myong-won retreated to Pyeongyang, the Japanese troops divided their objectives thus: the First Division would pursue the Korean king in Pyongan Province in the north (where Pyongyang is located); the Second Division would attack Hamgyong Province in the northeastern part of Korea; the Sixth Division would attack Jeolla Province at the southwestern tip of the peninsula; the Fourth Division would secure Gangwon Province in the mid-eastern part of the peninsula; and the Third, Fifth, Seventh, and Eighth Divisions would stabilize the following provinces respectively: Hwanghae Province (below Pyongan Province), Chungcheong Province (below Gyeonggi Province); Gyeongsang Province (in the southeast where the Japanese first had landed); and Gyeonggi Province (where the capital city is located).

Capture of Pyongyang
The First Division under Konishi Yukinaga proceeded northward, and sacked Pyongsan, Sohung, Pungsan, Hwangju, and Chunghwa on the way. At Chunghwa, the Third Division under Kuroda Nagamasa joined the First, and continued to the city of Pyongyang located behind the Taedong River. 10,000 Korean troops guarded the city against 30,000 Japanese under various commanders including the Generals Yi Il and Kim Myong-won, and their defense preparations had assured that no boats were available for Japanese use.

At night, the Koreans silently crossed the river and launched a successful surprise attack against the Japanese encampment. However, this alerted the rest of the Japanese army, which attacked the rear of the Korean positions and destroyed the remaining reinforcements crossing the river. Then the rest of the Korean troops retreated back to Pyongyang, and the Japanese troops gave up their pursuit of the Koreans to observe the way the Koreans crossed the river.

The next day, using what they had learned from observing the retreating Korean troops, the Japanese began sending troops to the other shore over the shallow points in the river, in a systematic manner, and at this the Koreans abandoned the city overnight. On 20 July 1592, the First and Third Divisions entered the deserted city of Pyongyang. In the city, they managed to gather 100,000 tons of military supplies and grain.

Campaigns in the Gangwon Province
The Fourth Division under the command of Mōri Yoshinari set out eastward from the capital city of Hanseong in July, and captured the fortresses down the eastern coast from Anbyon to Samcheok. The division then turned inward to capture Jeongseon, Yeongwol, and Pyeongchang, and settled down at the provincial capital of Wonju. There Mōri Yoshinari established a civil administration, systematized social ranks according to the Japanese model, and conducted land surveys. Shimazu Yoshihiro, one of the generals in the Fourth Division, arrived at Gangwon late, due to the Umekita Rebellion, and finished the campaign by securing Chunchon.

Campaigns in the Hamgyong Province and Manchuria
Katō Kiyomasa leading the Second Division of more than 20,000 men, crossed the peninsula to Anbyon with a ten-day march, and swept north along the eastern coast. Among the castles captured was Hamhung, the provincial capital of the Hamgyong Province, and here a part of the Second Division was allocated for defense and civil administration.

The rest of the division of 10,000 men continued north, and fought a battle on August 23 against the southern and northern Hamgyong armies under the commands of Yi Yong at Songjin (present-day Kimchaek). A Korean cavalry division took advantage of the open field at Songjin, and pushed the Japanese forces into a grain storehouse. There the Japanese barricaded themselves with bales of rice, and successfully repelled a formation charge from the Korean forces with their arquebuses. While the Koreans planned to renew the battle in the morning, Katō Kiyomasa ambushed them at night; the Second Division completely surrounded the Korean forces with the exception of an opening leading to a swamp. Here, those that fled were trapped and slaughtered.

Koreans who fled gave alarms to the other garrisons, allowing the Japanese troops easily to capture Kilchu, Myongchon, and Kyongsong. The Second Division then turned inland through Puryong toward Hoeryong where two Korean princes had taken refuge. On August 30, 1592, the Second Division entered into Hoeryong where Katō Kiyomasa received the Korean princess and the provincial governor Yu Yong-rip, these having already been captured by the local inhabitants. Shortly afterward, a Korean Warrior band handed over the head of an anonymous Korean general, and the General Han Kuk-ham tied up in ropes.

Katō Kiyomasa then decided to attack a nearby Jurchen castle across the Tumen River in Manchuria to test his troops against the "barbarians", as the Koreans called the Jurchens ("Orangkae" in Korean and "Orangai" in Japanese – the Japanese derived both the word and the concept of the Jurchens as barbarians from the Koreans). The Koreans with 3,000 men at Hamgyong joined in (with Kato's army of 8,000), as the Jurchens periodically raided them across the border. Soon the combined force sacked the castle, and camped near the border; after the Koreans left for home, the Japanese troops suffered a retaliatory assault from the Jurchens. Despite having the advantage, Katō Kiyomasa retreated with his forces to avoid heavy losses. Because of this invasion, rising Jurchen leader Nurhachi offered military assistance to Joseon and Ming in the war. However, the offer was refused by both countries, particularly Joseon, citing that it would be disgraceful to accept assistance from the "Barbarians" to the north.

The Second Division continued east, capturing the fortresses of Jongseong, Onsong, Kyongwon, and Kyonghung, and finally arrived at Sosupo on the estuary of the Tumen River. There the Japanese rested on the beach, and watched a nearby volcanic island rising on the horizon that they mistook as Mount Fuji. After the tour, the Japanese continued their previous efforts to bureaucratize and administrate the province, and allowed several garrisons to be handled by the Koreans themselves.

Naval battles of Admiral Yi
Having secured Pyeongyang, the Japanese planned to cross the Yalu River into Jurchen territory, and use the waters west of the Korean peninsula to supply the invasion. However, Yi Sun-sin, who held the post of the Left Naval Commander (equivalent of "Admiral" in English) of the Jeolla Province (which covers the western waters of Korea), successfully destroyed the Japanese ships transporting troops and supplies. Japan lacking enough arms and troops to carry on the invasion of the China, changed the objective of the war to the occupation of Korea.

When the Japanese troops landed at the port of Busan, Bak (also spelled Park) Hong, the Left Naval Commander of the Gyeongsang Province, destroyed his entire fleet, his base, and all armaments and provisions, and fled. Won Gyun, the Right Naval Commander, also destroyed and abandoned his own base, and fled to Konyang with only four ships. Therefore, there was no Korean naval activity around the Gyeongsang Province, and the surviving two, out of the four total navies, were active only on the other (west) side of the peninsula. Admiral Won later sent a message to Admiral Yi that he had fled to Konyang after being overwhelmed by the Japanese in a fight. A messenger was sent by Admiral Yi to the nearby island of Namhae to give Yi's order for war preparations, only to find it pillaged and abandoned by its own inhabitants. As soldiers began to flee secretly, Admiral Yi ordered "to arrest the escapees" and had two of the fugitives brought back, beheaded them and had their heads exposed.

Admiral Yi's battles steadily affected the war and put significant strain on Japanese supply routes.

Battle of Okpo
Admiral Yi relied on a network of local fishermen and scouting boats to receive intelligence of the enemy movements. On the dawn of June 13, 1592, Admiral Yi and Admiral Yi Eok-gi set sail with 24 Panokseons, 15 small warships, and 46 boats (i.e. fishing boats), and arrived at the waters of the Gyeongsang Province by sunset. Next day, the Jeolla fleet sailed to the arranged location where Admiral Won was supposed to meet them, and met the admiral on June 15. The augmented flotilla of 91 ships then began circumnavigating the Geoje Island, bound for the Gadeok Island, but scouting vessels detected 50 Japanese vessels at the Okpo harbor. Upon sighting the approaching Korean fleet, some of the Japanese who had been busying themselves with plundering got back to their ships, and began to flee. At this, the Korean fleet encircled the Japanese ships and finished them with artillery bombardments. The Koreans spotted five more Japanese vessels that night, and managed to destroy four. The next day, the Koreans approached 13 Japanese ships at Jeokjinpo as reported by the intelligence. In the same manner as the previous success at Okpo, the Korean fleet destroyed 11 Japanese ships – completing the Battle of Okpo without a loss of a single ship.



Battle of Sacheon and the Turtle Ship
About three weeks after the Battle of Okpo, Admirals Yi and Won sailed with a total of 26 ships (23 under Admiral Yi) toward the Bay of Sacheon upon receiving an intelligence report of the Japanese presence. Admiral Yi had left behind his fishing vessels that used to make up most of his fleet in favor of his newly completed Turtle ship.

The turtle ship was a vessel of a Panokseon design with the removal of the elevated command post, the modification of the gunwales into curved walls, and the addition of a roof covered in iron spikes (and hexagonal iron plates, which is disputed  ). Its walls contained a total of 36 cannon ports, and also openings, above the cannon, through which the ship's crew members could look out and fire their personal arms. This design also prevented enemies from boarding the ship and aiming at the personnel inside. The ship was the fastest and most maneuverable existing warship in the East Asian theater, as it was powered by two sails and 80 oarsmen taking turns to handle the ship's 16 oars. No more than six Turtle Ships served throughout the entire war, and their primary role was to cut deep into the enemy lines, cause havoc with its cannon, and destroy the enemy flag ship.

On July 8, 1592, the fleet arrived at the Bay of Sacheon, where the outgoing tide prevented the Korean fleet from entering. Therefore, Admiral Yi ordered the fleet to feign withdrawal, which the Japanese commander observed from his tent on a rock. Then the Japanese hurriedly embarked their 12 ships and pursued the Korean fleet. The Korean navy counterattacked, with the Turtle Ship in the front, and successfully destroyed all 12 ships. Admiral Yi was shot by a bullet in his left shoulder, but survived.

Battle of Danghangpo
Admiral Yi Eok-gi with his fleet joined Admirals Yi Sun-sin and Won Gyun, and participated in a search for enemy vessels in the Gyonsang waters. On July 13, the generals received intelligence that a group of Japanese ships including those that escaped from the Battle of Dangpo was resting in the Bay of Danghangpo. Having traveled through a narrow gulf, the Koreans sighted a total of 26 enemy vessels in the bay. The turtle ship was used to penetrate the enemy formation and rammed the flagship, while the rest of the Korean fleet held back. Then Admiral Yi ordered a fake retreat, as the Japanese commander could escape to land while in the bay. When the Japanese commander pursued the Koreans far enough, the Korean fleet turned and surrounded the Japanese fleet, with the Turtle Ship again ramming against the enemy flag ship. The Japanese commanders were unable to counter the Korean cannon. Only 1 Japanese ship managed to escape from this rout, and that too was caught and destroyed by a Korean ship the next morning.



Battle of Hansando
In response to the Korean navy's success, Toyotomi Hideyoshi recalled three commanders from land-based activities: Wakizaka Yasuharu, Kato Yoshiaki, and Kuki Yoshitaka. They were the first commanders with naval responsibilities in the entirety of the Japanese invasion forces. However, the commanders arrived in Busan nine days before Hideyoshi's order was actually issued, and assembled a squadron to counter the Korean navy. Eventually Wakizaka completed his preparations, and his eagerness to win military honor pushed him to launch an attack against the Koreans without waiting for the other commanders to finish.

The combined Korean navy of 53 ships under the commands of Admirals Yi Sun-sin and Yi Ok-gi was carrying out a search-and-destroy operation because the Japanese troops on land were advancing into the Jeolla Province. The Jeolla Province was the only Korean territory to be untouched by a major military action, and served as home for the three commanders and the only active Korean naval force. The admirals considered it best to destroy naval support for the Japanese to reduce the effectiveness of the enemy ground troops.

On August 13, 1592, the Korean fleet sailing from the Miruk Island at Dangpo received local intelligence that a large Japanese fleet was nearby. The following morning, the Korean fleet spotted the Japanese fleet of 82 vessels anchored in the straits of Gyeonnaeryang. Because of the narrowness of the strait and the hazard posed by the underwater rocks, Admiral Yi sent six ships to lure out 63 Japanese vessels into the wider sea, and the Japanese fleet followed. There the Japanese fleet was surrounded by the Korean fleet in a semicircular formation called "crane wing" by Admiral Yi. With at least three turtle ships (two of which were newly completed) spearheading the clash against the Japanese fleet, the Korean vessels fired volleys of cannonballs into the Japanese formation. Then the Korean ships engaged in a free-for-all battle with the Japanese ships, maintaining enough distance to prevent the Japanese from boarding; Admiral Yi permitted melee combats only against severely damaged Japanese ships. The battle ended in a Korean victory, with Japanese losses of 59 ships – 47 destroyed and 12 captured. Several Korean prisoners of war were rescued by the Korean soldiers throughout the fight. Wakisaka escaped due to the speed of his flag ship. When the news of the defeat at the Battle of Hansando reached Toyotomi Hideyoshi, he ordered that the Japanese invasion forces cease all naval operations.

Battle of Angolpo
On August 16, 1592, Yi Sun-sin led their fleet to the harbor of Angolpo where 42 Japanese vessels were docked. When Admiral Yi tried to fake a retreat, the Japanese ships did not follow; in response, Admiral Yi ordered the Korean ships to take turns bombarding the Japanese vessels. In fear that the Japanese troops would take revenge for their losses against the local inhabitants, Admiral Yi ordered the Korean ships to cease fire against the few remaining enemy vessels.

Korean Militias
From the beginning of the war, the Koreans organized militias called the "Righteous Army" (의병) to resist the Japanese invasion. These fighting bands were raised throughout the country, and participated in battles, guerilla raids, sieges, and the transportation and construction of wartime necessities.

There were three main types of Korean militias during the war: first, the surviving and leaderless Korean regular soldiers; second, the "Righteous Armies" consisting of patriotic yangbans (aristocrats) and commoners; and third, the Buddhist monks.

During the first invasion, the Jeolla Province remained the only untouched area on the Korean peninsula. In addition to the successful patrols of the sea by Admiral Yi, the activities of volunteer forces pressured the Japanese troops to avoid the province for other priorities.

Gwak Jae-u's Campaigns along the Nakdong River
Gwak Jae-u was a famous leader in the Korean militia movement, and it is widely accepted that he was the first to form a resistance group against the Japanese invaders. He was a land-owner in the town of Uiryong situated by the Nam River in the Gyeongsang Province. As the Korean regulars abandoned the town and an attack seemed imminent, Gwak organized fifty townsmen; however the Third Division went from Changwon straight toward Songju. When Gwak used abandoned government stores to supply his army, the Gyeongsang Province Governor Kim Su branded Gwak's group as rebels, and ordered that it be disbanded. When the general asked for help from other landowners, and sent a direct appeal to the King, the governor sent troops against Gwak, in spite of having enough troubles already with the Japanese. However, an official from the capital city then arrived to raise troops in the province, and, since the official lived nearby and actually knew him, he saved Gwak from troubles with the governor.

Gwak Jae-u deployed his troops in guerilla warfare under the cover of the tall reeds on the union of the Nakdong and the Nam Rivers. This strategy prevented easy access for the Japanese troops to the Jeolla Province where Admiral Yi and his fleet were stationed.

Battle of Uiryong/Chongjin
The Sixth Division under the command of Kobayakawa Takakage was in charge of conquering the Jeolla Province. The Sixth Division marched to Songju through the established Japanese route (i.e. the Third Division, above), and cut left to Geumsan in Chungcheong, which Kobayakawa secured as his starting base for his invasion of the province.

Ankokuji Ekei, a former Buddhist monk made into a general due to his role in the negotiations between Mōri Terumoto and Toyotomi Hideyoshi, led the units of the Sixth Division charged with the invasion of the Jeolla Province. The units began their march to Uiryong at Changwon, and arrived at the Nam River. Ankokuji's scouts planted meters measuring the river's depths so that the entire squadron could cross the river; over the night, the Korean militiamen moved the meters into the deeper parts of the river. As the Japanese troops began to cross, Gwak's militia ambushed them, and caused heavy losses for the Japanese. In the end, to advance into the Jeolla Province, Ankokuji's men had to try going north around the insecure grounds and within the security of the Japanese-garrisoned fortresses. At Kaenyong, Ankokuji's target was changed to Gochang, to be taken with the aid of Kobayakawa Takakage. However, the entire Jeolla campaign was then abandoned when Kim Myeon and his guerillas successfully ambushed Ankokuji's troops by firing arrows from hidden positions within the mountains.

Jeolla Coalition and Battle of Yongin
When the Japanese troops were advancing to Hanseong (present-day Seoul), Yi Kwang, the governor of Jeolla Province, attempted to check the Japanese progress by launching his army toward the capital city. Upon hearing the news that the capital had already been sacked, the governor withdrew his army. However, as the army grew in size to 50,000 men with the accumulation of several volunteer forces, Yi Kwang and the irregular commanders reconsidered their aim to reclaim Hanseong, and led the combined forces north to Suwon, 26 miles (42 km) south of Hanseong. On June 4, an advance guard of 1,900 men attempted to take the nearby fortress at Yong-in, but the 600 Japanese defenders under Admiral Wakizaka Yasuharu avoided engagement with the Koreans until June 5, when the main Japanese troops came to relieve the fortress. The Japanese troops counterattacked successfully against the Jeolla coalition, forcing the Koreans to abandon arms and retreat.

First Geumsan Campaign
Around the time of General Kwak's mobilization of his volunteer army in the Gyeongsang Province, Go Gyeong-myeong in Jeolla Province formed a volunteer force of 6,000 men. Go then tried to combine his forces with another militia in the Chungchong Province, but upon crossing the provincial border he heard that Kobayakawa Takakage of the Sixth Division had launched an attack on Jeonju (the capital of Jeolla Province) from the mountain fortress at Geumsan. Go returned to his own territory. Having joined forces with General Gwak Yong, Go then led his soldiers to Geumsan. There, on July 10, the volunteer forces fought with a Japanese army retreating to Geumsan after a defeat at the Battle of Ichi two days earlier on July 8

Siege of Jinju
Jinju (진주) was a strategic stronghold that defended Kyongsang Province. The Japanese commanders knew that control of Jinju would mean easy access to the ricebelts of Jeolla Province. Therefore, a large army under Hosokawa Tadaoki approached Jinju. Jinju was defended by Kim Simin (김시민), one of the better generals in Korea, commanding a Korean garrison of 3,000 men. Kim had recently acquired about 200 new arquebuses that were equal in strength to the Japanese guns. With the help of arquebuses, cannon, and mortars, Kim and the Koreans were able to drive back the Japanese from Jeolla Province. The battle at Jinju is considered one of the greatest victories of Korea because it prevented the Japanese from entering Jeolla Province.

Intervention of Ming China
The Koreans could not hope to expel the Japanese from their land by themselves. Despite the various logistical and organizational difficulties suffered by the Japanese, Korea ultimately had to rely on an external factor, the intervention of Ming China, to halt the advance of the first Japanese invasion.

Korean Court historian Yu Song-nyong stated that the Korean naval victory stalled the entire strategy of the invaders by "cutting off one of the arms" with which Japan tried to envelop Korea, isolating Konishi Yukinaga's army at P'yongyang and securing Chinese waters from the feared Japanese attack, such that "the Celestial Army could come by land to the assistance" of Korea.

Viewing the crisis in Choson, the Ming Dynasty Wanli emperor and his court was initially filled with confusion and skepticism on how their tributary could have been overrun so quickly.

The Korean Court was at first hesitant to call for help from the Ming Dynasty, and began a withdrawal to Pyongyang. The local governor at Liaodong eventually acted upon King Seonjo's request for aid following the capture of Pyongyang by sending a small force of 5,000 soldiers led by Zu Chengxun. This cavalry force advanced almost unhindered and managed to enter Pyongyang, but was promptly and decisively defeated by the Japanese troops in the city. One of their leading generals, Shi Ru, was killed in this engagement. During the later half of 1592, the Ming sent investigation teams into Pyongyang to clarify the situation. The Ming became fully aware of the situation and made the decision for a full reinforcement by September 1592.

By then it had become clear that this was a situation much more serious than something that could be handled by local forces. Thus the Ming Emperor mobilized and dispatched a larger force in January 1593 under the general Li Rusong and Imperial Superintendent Song Yingchang, the former being one of the sons of Ming dynasty's Liaodong military magistrate Li Chengliang and the latter being a bureaucratic officer (Ming military law stipulated that any military officer would have an accompanying bureaucrat appointed by the Imperial Court acting as the general's superior). According to the collection of letters left by Song Yingchang, the strength of the Ming army was around 40,000 - composed mostly of garrisons from the north, including around 3,000 men with experience against Japanese pirates under Qi Jiguang.

Siege of Pyongyang
On January 5, 1593, the Ming expeditionary army arrived outside Pyongyang accompanied by a group of Korean soldiers. By King Seonjo's decree, Ming general Li Rusong was appointed the supreme commander of all armies in Korea. After initial attempts to negotiate with the Japanese defenders under Konishi Yukinaga broke down, the two sides began skirmishing on the outskirts over the next couple of days, with the Li Rusong attempting to dislodge a Japanese garrison on the hills north of the city while the Konishi Yukinaga attempted a night raid on the Ming camp.

On the morning of January 8, Li ordered an all-out assault on three sides of the city; Japanese defenders were forced off the walls fairly quickly, and retreated to the citadel they built on the eastern portions of the city. The allies were unwilling to commit to a direct assault on the heavily defended fortification during the day, instead they left an opening for the Japanese to rally while making preparations for a fire assault on their position at night. Japanese forces sallied out of the undefended eastern walls and made a run for Seoul, and they were hit with additional ambushes on the way back south and took heavy casualties. Song YingChang's letters on March the 1st 1593 describing the battle in full to the Ming court After their defeat, the Japanese shifted their strategy to hit-and-run tactics and ambushes. The use of gunpowder technology and street fighting contributed to the victory, which would permanently deter the invasion.

Battle of Byeokjegwan
Soon after retaking Pyongyang, Li also succeeded in retaking the major city of Kaesong on 19 January and met only minor resistance from the Japanese defenders.

Overconfident with his recent success and possibly misled by false reports, Li Rusong advanced towards the capital city of Seoul on January 21 of 1592. His personally led small force of elite cavalry numbered somewhere around 3,000, along with a small force of Koreans and advance scouts. On January 26, the force ran into an unexpected confrontation at Byeokjegwan by a large Japanese formation of about 30,000.

Initially, the scouting party of the group under Cha Da Sho and a Korean general confronted a small band of Japanese numbering no more than 600 men. The party overran them successfully but soon ran into a much larger host under Tachibana Muneshige, and retreated to a nearby hill to defend themselves.

Upon hearing of his scouting party's plight, Li decided to rush forward with the rest of his small host. He met up with his scouting party around noon, but by that time even more Japanese forces were converging on the area.

The Ming forces gradually retreated north while fighting off several waves of attacks. Li Rusong and many other generals personally fought in the brawl, and they sustained heavy casualties before they met up with the rest of their army toward the later portion of the day. At this point, the Japanese gave up further attacks and both sides pulled back. Because the Ming suffered heavy casualties among their elite retinues, Li became reluctant to move aggressively for the remainder of the war.

Battle of Haengju
The Japanese invasion into Jeolla province was broken down and pushed back by General Gwon Yul at the hills of Ichiryeong, where outnumbered Koreans fought overwhelming Japanese troops and gained victory. Gwon Yul quickly advanced northwards, re-taking Suwon and then swung south toward Haengju where he would wait for the Chinese reinforcements. After he got the message that the Ming army under Li Rusong was pushed back at Byeokje, Gwon Yul decided to fortify Haengju.

Bolstered by the victory at Battle of Byeokjegwan, Katō and his army of 30,000 men advanced to the south of Hanseong to attack Haengju Fortress, an impressive mountain fortress that overlooked the surrounding area. An army of a few thousand led by Gwon Yul was garrisoned at the fortress waiting for the Japanese. Katō believed his overwhelming army would destroy the Koreans and therefore ordered the Japanese soldiers to simply advance upon the steep slopes of Haengju with little planning. Gwon Yul answered the Japanese with fierce fire from the fortification using Hwachas, rocks, handguns, and bows. After nine massive assaults and 10,000 casualties, Katō burned his dead and finally pulled his troops back.

The Battle of Haengju was an important victory for the Koreans, as it greatly improved the morale of the Korean army. The battle is celebrated today as one of the three most decisive Korean victories; Battle of Haengju, Siege of Jinju (1592), and Battle of Hansando.

Today, the site of Haengju fortress has a memorial built to honor Gwon Yul.

Stalemate
After the Battle of Byeokjegwan, the Ming army took a cautious approach and moved on Seoul again later in February after the successful Korean defense in the Battle of Haengju.

The two sides remained at a stalemate between the Kaesong to Seoul line for the next couple of months and both sides were unable and unwilling to commit to further offensives. The Japanese were still unable to gain sufficient supplies to move north, and the defeat at Pyongyang had caused part of the Japanese leadership such as Konishi Yukinaga and Ishida Mitsunari to seriously consider negotiating with the Ming dynasty forces. This got them into a heated debate with other hawkish generals such as Kato Kiyomasa, and these conflicts would eventually have further implications in events in Japan following the war. (see Battle of Sekigahara)

The Ming forces on the other hand, were also facing their own set of problems. Soon after arriving in Korea the Ming officials began to note the inadequate logistical supply from the Korean court. The records by Qian Shizhen noted that even after the siege of Pyongyang the Ming forces were already stalled for nearly a week due to the lack of supplies before moving on to Kaesong, as the time went on the situation only become more serious. When the weather warmed the road condition in Korea also became terrible, as numerous letters from Song Yingchang and other Ming officers attest, which made resupplying from China itself also a tedious process.

The Korean countryside was already devastated from the invasion when the Ming forces arrived, and in the heart of winter it was extremely difficult for the Koreans to muster sufficient supplies. Even though the court had assigned the majority of the men on hand to tackle the situation, their desire to reclaim their country along with the militarily inexperienced nature of many of their administrators resulted in them continually requesting the Ming forces to advance despite the situation. These events created an increasing level of distrust between the two sides.

Though by mid April 1593, faced with ever greater logistical pressure from a Korean naval blockade of Admiral Yi in addition to a Ming force special operation that managed to burn down a very significant portion of the Japanese grain storage the Japanese decided to break off into talks and pull out of Seoul.

Negotiations and truce between China and Japan (1594–1596)


There were two factors that triggered the Japanese to withdraw: first, a Chinese commando penetrated Seoul and burned storehouses at Yongsan, destroying most of what was left of the Japanese troops depleted stock of food. Secondly, Shen Wei Ching made another appearance to conduct negotiations, and threatened the Japanese with an attack by 400,000 Chinese. The Japanese under Konishi and Kato, aware of their weak situation, agreed to withdraw to the Pusan area while the Chinese would withdraw back to China. A ceasefire was imposed, and a Ming embassy was be sent to Japan to discuss peace terms.

By May 18, 1594, all the Japanese soldiers had retreated to the area around Busan and many began to make their way back to Japan. The Ming government withdrew most of its expeditionary force, but kept 16,000 men on the Korean peninsula to guard the truce.

Once peace negotiations between China and Japan finally got underway, for some unknown reason Chinese negotiators gave the Ming Emperor the mistaken impression that he was about to deal with a minor state that had been subdued by war. Furthermore, they conveyed the idea that the Japanese regent, Hideyoshi, was prepared to become his vassal. Under such conditions, the Chinese sought to resolve the issue in their favor by including Japan in their tributary system of foreign relations. They would establish Hideyoshi as king of Japan and grant him the privilege of formal tribute trade relations with the Ming dynasty.

In Japan, Hideyoshi's negotiators apparently led him to believe that China was suing for peace and ready to accept him as their emperor. Thus, Hideyoshi issued the demands of a victor; first, a daughter of the Ming emperor must be sent to become the wife of the Japanese emperor;  second, the southern provinces of Joseon must be ceded to Japan;  third, normal trade relations between China and Japan must be restored;  and fourth, a Joseon prince and several high-ranking government officials must be sent to Japan as hostages. Bargaining from such fundamentally different perspectives, there was no prospect whatsoever for these talks to succeed. Early in 1597, both sides resumed hostilities.

Proposal for military reforms
During the period between the First and Second invasions, the Korean government had a chance to examine the reasons why they had been easily overrun by the Japanese. Yu Seong-ryong, the Prime Minister, spoke out about the Korean disadvantages.

Yu pointed out that Korean castle defenses were extremely weak, a fact which he had already pointed out before the war. He noted how Korean castles had incomplete fortifications and walls that were too easy to scale. He also wanted cannons set up in the walls. Yu proposed building strong towers with gun turrets for cannons. Besides castles, Yu wanted to form a line of defenses in Korea. In this kind of defense, the enemy would have to scale many walls in order to reach Seoul.

Yu also pointed out how efficient the Japanese army was, since it took them only one month to reach Seoul, and how well organized they were. Yu noted how the Japanese moved their units in complex maneuvers, often weakening the enemy with arquebuses, then attacking with melee weapons.

Military Training Agency
King Seonjo and the Korean court finally began to reform the military. In September 1593, the Military Training Agency was established. The agency carefully divided the army into units and companies. Within the companies were squads of archers, arquebusers, swordsmen, and spear infantry. The agency set up divisional units in each region of Korea and garrisoned battalions at castles. The agency, which originally had less than 80 members, soon grew to about 10,000.

One of the most important changes was that both upper class citizens and slaves were subject to the draft. All males had to enter military service be trained and familiarized with weapons.

It was also around this time that the military scholar Han Gyo (한교) wrote the martial arts manual Muyejebo based on the book Ji Xiao Xin Shu written by the famous Chinese general Qi Jiguang.

Second invasion (1597–1598)
After the failed peace negotiations of the inter-war years, Hideyoshi launched the second invasion of Korea. One of the main strategic differences between the first and second invasions was that conquering China was no longer an explicit goal for the Japanese. Failing to gain a foothold during Katō Kiyomasa's Chinese campaign and the near complete withdrawal of the Japanese forces during the first invasion had established that the Korean peninsula was the more prudent and realistic objective.

Soon after the Chinese ambassadors had safely returned to China in 1597, Hideyoshi sent approximately 200 ships with and estimated 141,100 men under the overall command of Kobayakawa Hideaki. Japan's second force arrived unopposed on the southern coast of Gyeongsang Province in 1596. However, the Japanese found that the Korean army was both better equipped and better prepared to deal with an invasion. In addition, upon hearing the news in China, the imperial court in Beijing appointed Yang Hao (楊鎬) as the supreme commander of an initial mobilization of 55,000 troops from various (and sometimes remote) provinces across China, such as Sichuan, Zhejiang, Huguang, Fujian, and Guangdong. A naval force of 21,000 was included in the effort. Rei Huang, a Chinese historian, estimated that the combined strength of the Chinese army and navy at the height of the second campaign was around 75,000. Korean forces totaled approximately 30,000 with General Gwon Yul's army in Gong Mountain (공산; 公山) in Daegu, General Gwon Eung's (권응) troops in Gyeongju, Gwak Jae-u's soldiers in Changnyeong (창녕), Yi Bok-nam's (이복남) army in Naju, and Yi Si-yun's troops in Chungpungnyeong.

Initial offensive
Initially the Japanese found limited success, being largely confined to Gyeongsang Province and only launching numerous raids to harass and weaken the Korean defenders. In the early Autumn of 1597, the Japanese began a more focused and sustained advance. The Japanese planned to attack Jeolla Province in the southwestern part of the peninsula and eventually occupy Jeonju, the provincial capital. Korean success in the Siege of Jinju in 1592 had mostly saved this area from devastation during the first invasion. Two Japanese armies, under Mōri Hidemoto and Ukita Hideie, began the assault in Busan and marched towards Jeonju, taking Sacheon and Changpyong along the way.

Plot dismissal of Admiral Yi


The Korean navy was again to play a crucial part in the second invasion, as in the first, by hampering Japanese advances on land by harassing supply fleets at sea.

The Japanese were well aware of the risks that the Korean navy posed to their supply lines. The removal of Admiral Yi, who was responsible for much of the Korean naval success in the first phase of the invasion, would be beneficial to the objectives of the Japanese army, as the success of the Korean navy was largely a result of his leadership efforts. Through infighting within the Korean court, and due to Yi's refusal to obey direct orders of the Korean court, Yi was ultimately both demoted and jailed by King Seonjo. This development allowed others within the court to further advance their personal agendas. Ultimately it was Won Gyun who was appointed in Admiral Yi's place at the head of Korean navy.

Battle of Chilcheollyang
The success of these Japanese covert actions within the Korean court would quickly affect their fortunes in their campaign at sea. After Won Gyun replaced Admiral Yi as head of the navy, he was quick to take action and justify his newly acquired position. He gathered the entire Korean fleet, which now had more than 100 ships outside of Yosu, to search for the Japanese. Without any previous preparations or planning, Won Gyun then had his entire fleet sail towards Busan.

After one day at sea, Won Gyun was informed of a large Japanese fleet near Busan. He decided to attack immediately, despite reports of exhaustion among the crew of the ship.

At the subsequent Battle of Chilcheollyang, Won Gyun was completely outmaneuvered by the Japanese in a surprise attack. His ships were overwhelmed by arquebus fire and the traditional Japanese boarding attacks, and largely resulted in the destruction of his entire fleet. In a stroke of luck for the Korean forces, the defection before the battle of Bae Soel, an officer who did not submit to Won Gyun leadership, allowed the preservation of thirteen panokseons which would form the entire fighting force of the Korean Navy during the immediately following months. The Battle of Chilcheollyang was one of Japan's most effective naval victories of the entire war. Won Gyun was himself killed by a Japanese garrison after he struggled ashore on an island after the destruction of his flagship. The Japanese navy obliterated the Korean navy, and were operated correctly of their mission of escorting troop ships and supporting landing operations.

Siege of Namwon
After the disaster at Battle of Chilcheollyang, the allied defenses in the south began to quickly break down and the Japanese forces stormed into Jeolla province. The garrison of Namwon became their next key target.

Namwon was located thirty miles southeast of Jeonju. Correctly predicting a Japanese attack, a coalition force of 6,000 soldiers (including 3,000 Chinese troops under Yang Yuan and civilian volunteers) were prepared to fight the approaching Japanese forces. The Japanese laid siege to the walls of the fortress with ladders and siege towers. The two sides exchanged volleys with arquebuses and bows. Eventually the Japanese forces scaled the walls and sacked the fortress. According to Japanese commander Okochi Hidemoto, author of the Chosen Ki, the Siege of Namwon resulted in 3,726 casualties on the Korean and Chinese forces' side. Ultimately, the entire Jeolla Province fell under Japanese control, but as the campaign progressed, the Japanese found themselves hemmed in on all sides and were again forced to regroup back in a defensive perimeter around Gyeongsang Province.

Among the defenders, the Korean forces and its leaders were almost entirely killed. Only Yang Yuan managed to sally out after the walls were breached with a handful of men back to Seoul, although eventually he, too, was executed by the Ming court on the grounds of his defeat in battle.

Battle of Hwangseoksan
Hwangseoksan Fortress consisted of extensive walls that circumscribed the Hwangseok Mountains and garrisoned thousands of soldiers led by generals Jo Jong-do and Gwak Jun. When Katō Kiyomasa laid siege to the mountain with a large army, the Koreans lost morale and retreated with 350 casualties. The successful siege did not, however, lead to a subsequent advance from beyond Gyeongsang Province.

First Korean and Ming counter offensive
Upon the breakout of war during the second invasion, the Ming emperor was furious about the entire debâcle of the peace talks and turned his wrath on many of its chief supporters; namely, the minister of military department Shi Xin, who was deposed and jailed (he died a couple of years later in prison). In addition, the chief negotiator, Shen Wei-Jin, was executed. Xin Jie was named the new minister of military and Yang Hao as the new chief superintendent (Jin Lue) of Korea; Xin Jie himself was also stationed in Korea for the remainder of the war. The Ming leadership quickly pulled in many units from its border with Korea in the hope of turning the tide against the Japanese advance.

Battle of Jiksan
After the steady Japanese advances on land, they were ready to aim to assualt Seoul by late August – early September 1597. However, the attempt to attack Seoul was foiled by a Ming defense around Jiksan (modern day Cheonan).

Forces under Kuroda Nagamasa formed the vanguard of the right army and marched toward Seoul, which deeply disturbed the court at Seoul. Several of the Ming generals stationed in Korea suggested to the court that they pull back their forces until they could gather more reinforcements, but the Ming administrators overruled their generals and ordered them to make a stand. Thus the chief commander of the Ming forces at the time, Ma Gui, sent out General Jie Sheng (解生) and three other generals with an elite cavalry force to try to confront the Japanese forces.

According to Korean records, the Ming forces ran into the vanguard forces under Kuroda around the area of Jiksan. On the first day, they beat back a small scouting party. On the second day, the two forces clashed in earnest, with the Japanese being beaten back. Soon afterwards, a larger Japanese force showed up and the Ming forces also retreated. However, the Japanese did not take advantage and remained in the area of Jiksan, and withdrew back shortly afterwards. This battle greatly relieved the Joseon and Ming courts and was seen as the beginning of a turnaround in the land campaign.

Battle of Myeongnyang
After the debacle in Chilcheollyang, King Seonjo immediately reinstated Admiral Yi. Admiral Yi quickly returned to Yeosu only to find the majority of his navy destroyed. Yi re-organized the navy, now reduced to thirteen ships and approximately 200 men from the previous battle. Nonetheless, Admiral Yi's determination was not shaken, and on September 16, 1597, in the Myeongnyang Strait, he encountered a large Japanese fleet of approximately 133 warships, with a further 200 logistical ships in support, with only thirteen warships of his own. By making use of a narrow passage, Yi positioned his ships in a battle line that prevented the Japanese Navy from making any use of their numerical superiority. The Battle of Myeongnyang resulted in a Korean victory, with Admiral Yi retaking the naval initiative, and the Japanese fleet being forced to return to Busan, under the orders of Mōri Hidemoto. The Battle of Myeongnyang is considered Admiral Yi's greatest battle, largely as a result of the disparity of numbers.

Siege of Ulsan
By late 1597, the Joseon and Ming allied forces achieved victory in Jiksan and pushed the Japanese further south. After the news of the loss at Myeongnyang, Katō Kiyomasa and his retreating army looted Gyeongju, the former capital of Unified Silla.

The Japanese forces sacked the city and many artifacts and temples were destroyed, most prominently, the Bulguksa, a Buddhist temple. However, Joseon and Ming forces continued to harass the Japanese forces, who then withdrew further south to Ulsan, a harbor that had been an important Japanese trading post a century before, and which Katō had chosen as a strategic stronghold.

Admiral Yi's control of the areas around the Korean Strait permitted no supply ships to reach the western side of the Korean Peninsula, into which many extensive tributaries merge. Without provisions and reinforcements, the Japanese forces were constrained to the coastal fortresses, known as wajō, that they still controlled. The advancing Korean and Ming forces would attempt to take advantage of this situation, by attacking Ulsan. This siege was the first major offensive from the Ming and Korean forces in the second phase of the war.

The effort of the Japanese garrison (about 7,000 men) of Ulsan was largely dedicated to its fortification in preparation for the expected attack. Katō Kiyomasa assigned command and defense of the base to Katō Yasumasa, Kuki Hirotaka, Asano Nagayoshi, and others before proceeding to Sosaengpo. The Ming and Korean army's first assault on January 29, 1598, caught the Japanese Army unaware and still encamped, for the large part, outside Ulsan's unfinished walls.

A total of around 36,000 troops with the help of singijeons and hwachas nearly succeeded in sacking the fortress, but reinforcements under the overall command of Mōri Hidemoto came across the river to aid the besieged fortress. Although the Japanese garrison was desperately short of supplies, the Ming commander Ma Gui judged the situation to be going against the allies; as more and more Japanese forces began to arrive from the surrounding area and the allied forces were quickly becoming outnumbered. Late one night, Ma Gui decided to order a general organized retreat of the allied forces, but soon confusion set in, and matters were further complicated by heavy rainfall and harassing attacks by the Japanese. The chief superintendent Yang Hao panicked and left hastily for Seoul ahead of the army.

The general retreat quickly turned into a chaotic rout; which the Japanese took quick advantage of by attacked the retreating Ming and Korean forces. The disaster was a heavy setback for Korea, who would not be in a position to move on the Japanese position again for more than eight months.

Final allied offensive of 1598
After the Siege at Ulsan, the two sides remained in a stalemate for the next several months. Xin Jie decided that they would require further reinforcements to launch a final large offensive to permanently end the Japanese presence on the Korean Peninsula.

Reinforcements from China began to pour in through most of mid 1598, with Chen Lin and Deng Zilong and their navy arriving in May. By September 1598, the Ming presence in Korea had swelled to 75,000 overall, by far the largest at any point in the war.

Xin Jie divided his forces into four groups, with Ma Gui heading the offensive against Ulsan yet again, Li Rumei heading the offensive against Sacheon, Chen Lin commanding the navy and along with Liu Ting and Yi Sun-Sin with a coordinated land-sea effort against Suncheon.

Just before they set out, however, news came that Li Rusong was killed by Mongolian tribesmen back in Liao Dong. Xin Jie decided to remove his emotionally weakened brother Li Rumei in favor of Dong Yi Yuan.

In June 1598, after Commander Konishi Yukinaga raised concerns about the supply situation and limited prospects for further territorial gains in the peninsula, 70,000 troops were withdrawn back to Japan, with only 60,000 left behind to guard the territory still under Japanese control. These forces were mostly Satsuma soldiers of the Shimazu clan under commanders Shimazu Yoshihiro and his son Tadatsune. Kato Kiyomasa remained in command of the defenses of Ulsan while Konishi himself commanded the defenses at Suncheon.

The forces at Sacheon and Ulsan continued to be engaged in a military deadlock in the months that followed.

Battle of Sacheon
The Chinese believed that Sacheon was crucial to their goal of retaking the lost castles in Korea and ordered a general attack. Although the Chinese made initial progress, the tide of battle turned when Japanese reinforcements attacked the rear of the Chinese Army and the Japanese soldiers inside the fortress sallied from the gates and counter-attacked. The Chinese Ming forces retreated with 30,000 losses, with Japanese maintaining an orderly pursuit.

According to Chinese and Korean sources concerning the battle, the forces led by Dong Yi Yuan were making progrees in the siege until a sudden gunpowder accident caused an explosion in their camp and the Japanese were able to take advantage of the situation to rout the confused and weakened allies.

Death of Hideyoshi
After the death of Hideyoshi on September 18, 1598, the Council of Five Elders ordered the withdrawal of all forces from Korea. Hideyoshi's death was kept a secret by the Council to preserve the morale of the army. The decree to withdraw was sent to the Japanese commanders in late October.

Battle of Noryang Point
The Battle of Noryang Point was the final naval battle in the war. The Korean Navy, under Admiral Yi, had recovered from its losses and was aided by the Chinese Navy under Chen Lin. Intelligence reports revealed that approximately 500 Japanese ships were anchored in the narrow straits of Noryang. The fleet was sent in preparation to withdraw the remaining Japanese troops, but this was not known to the Korean and Ming forces at the time. Noting the narrow geography of the area, Admiral Chen Lin, who led Deng Zilong and Yi Sun-sin, made a surprise attack against the Japanese fleet, under the cover of darkness on December 16, 1598, using cannon and fire arrows.

By dawn, nearly half of the Japanese fleet was scattered. As the Japanese began to withdraw, Admiral Yi ordered a final charge to destroy the remaining ships. As Yi's flagship sped forward, he was hit with a fatal shot to the left side of his chest. This was the third time he was shot throughout the course of the war. Yi told his captains to keep his death a secret and to continue the battle so that the morale of the soldiers would not drop. Admiral Yi died in minutes. Only three nearby captains, including his nephew, witnessed his death. Despite suffering high causalities, in the end the battle was a tactical victory for the Korean and Ming forces and resulted in the loss of over half of the Japanese fleet.

Postwar negotiations
As Tsushima suffered greatly from its loss of trade with Korea as a result of the invasions, Yoshitoshi of the Sō family, then dominant in Tsushima, undertook to spearhead peace talks and sent four peace negotiation missions to Korea in 1599 to normalize relations. The first three were captured and sent directly to Beijing by Chinese troops, but the fourth one in 1601 successfully obtained from the Korean court the promise of normalizing relations upon the return of remaining Korean captives. As Chinese troops continued to be present in Korea following the withdrawal of Japanese forces, the major incentive for Korea for the normalization of relations with Japan was the withdrawal of the Chinese soldiers off their territory. The Ming Chinese themselves were causing as much havoc as the Japanese had during the actual conflict, and their presence continued to strain the local economy and infrastructure. In response to the Korean request, Yoshitoshi promptly released several Korean prisoners and between 1603 and 1604 helped the Korean envoys in repatriating a further 3,000 by organizing a negotiation at Kyoto with Tokugawa Ieyasu, then the Shogun of Japan.

In the continuation of the diplomatic talks toward peaceful relations, Korea in 1606 expanded its conditions and demanded the Shogun write a formal letter requesting peace, and to extradite the Japanese soldiers who had defiled the royal tombs near Seoul. Realizing that the Shogunate would never agree to such a request, Yoshitoshi sent a forged letter and a group of criminals instead; but despite the clear fraud, the great need to dispel the Chinese soldiers pushed the Koreans to accept and send an embassy in 1608. The end result was a return of Korean prisoners and the restoration of diplomatic and trade relations between the two countries.

Aftermath and conclusion
The Japanese invasions were Asia's first regional wars involving massive armies equipped with modern era weapons. The conflict saw the regular employment of Japanese armies sizing up to 200,000, Chinese armies of 80,000, and ongoing engagement of local Korean forces in the hundreds of thousands.

The invasions also stood as a challenge to the existing Chinese world order on two levels: the military, in which the war reaffirmed Ming China's status as the supreme military power in East Asia, and the political, in which the war affirmed Chinese willingness to aid in the protection of its tributary/suzerain states.

Losses and gains
Contrary to Toyotomi Hideyoshi's intentions, the cost of the Japanese invasions of Korea significantly weakened the Toyotomi clan's power in Japan. After Hideyoshi's death, Toyotomi Hideyori became head of the Toyotomi clan. However, the loss of prestige and power resulted in a continuation of internal conflict in Japan. The losses suffered by varying Daimyo during the campaign were a contributing factor to the balance of power in Japan after the war. As the western based Daimyo of Kyushu and western Honshu (partially by geographic convenience) contributed the majority of the forces used during the Korean conflict, it left the pro-Hideyoshi alliance weakened for the eventual struggle with the mostly eastern backed forces of Tokugawa Ieyasu. Tokugawa would go on to unify Japan and establish himself as Shogun in 1603 following the decisive Battle of Sekigahara over a coalition of mostly western-based Daimyo.

Ming China also sustained a heavy financial burden for its role in defending Korea, while also fighting several other conflicts that same decade. The war also indirectly weakened their position in Manchuria, which gave the fledgling Manchu chieftain Nurhachi an opportunity to expand his influence and territory. (Nurhachi's expansions would culminate in the rise of the Qing Dynasty).

Given the conflict was fought exclusively on Korean soil, Korea ultimately suffered the most damage out of the three participants. In many ways, the invasions proved to be more devastating than any other event in the nation's history (even, arguably, more so than the Korean War). The peninsula suffered a reduction of arable land to sixty-six percent of the prewar total greatly hurt Korea's mainly agricultural economy; in the years that followed, famine, disease, and rebellions ran rampant throughout Korea. Significant losses of historical archives, cultural, as well as scientific artifacts (such as the water clock Ja-gyuk-roo ), and skilled artisans resulted in a waning of Korean science.

The total military and civilian casualties, as estimated by the late 19th-century historian, Geo H. Jones, is 1 million, and the total combat casualty is estimated at approximately 250,000-300,000. A total of 185,738 Korean and 29,014 Chinese casualties occurred, and an estimated 50,000 to 60,000 captives were taken by the Japanese throughout the war. Among those captured, a total of 7,500 were later returned to Korea through diplomatic means at the conclusion of the conflict. A large portion of the remaining captives were sold to European traders — mainly Portuguese, who then resold them in Southeast Asia.

The captives brought to Japan, including scholars, craftsmen, medicine makers, and gold smelters, provided to Japan many cultural and technological gains. In the years that followed, Japanese pottery and art was advanced and developed a significant similarity to their Korean counterparts. Advancements in other areas was also aided by technology and artisans acquired and captured during the invasions. Japanese typography was advanced with the adoption of Chinese fonts. As Korean pottery was highly prized in Japan, many Japanese lords established pottery-producing kilns with captured Korean potters in Kyūshū and other parts of Japan. The production of porcelain (Arita) in Japan began in 1616 at the town of Imari with the aid of Korean potters who had been enticed to relocate there after the war.

War brutality
As was typical in most prolonged military conflicts of the period, the war resulted in many instances of war brutality on all sides.

According to Stephen Turnbull, Japanese troops engaged in crimes against civilians in battles and often killed indiscriminately. Scorched earth policies were often employed, and farm animals were often slaughtered to prevent their use by Joseon or Ming forces. Outside of the main battles, raids to acquire foods and supply from civilians were common Captured prisoners were often mistreated or worked to near-death by starvation and neglect. The Japanese also collected the ears and noses of defeated soldiers as proof of their exploits on the battlefield and of casualty counts. The high casualty rate of the Joseon and Ming forces, and the large number of noses collected during the campaign was enough to build a large mound near Hideyoshi's Great Buddha, called the Mimizuka, or the "Mound of Ears".

Korean armies were also known to forcefully acquire food and supplies from civilians, both on an individual and organized level. Korean bandits and highwaymen also took advantage of the chaos during the war to form raiding parties and rob other Koreans. The inhabitants of Hamgyong Province (in the northern part of the Korean Peninsula) on occasion surrendered their fortresses, turning in their generals and governing officials to the Japanese invaders, as they felt oppressed by the Joseon government.

The Ming forces arriving in support of Joseon were oftentimes no better than the Japanese in the amount of destruction they caused and the degree of the crimes they committed. Ming forces often did not distinguish between loyal Joseon civilians and Japanese collaborators. In one notable case the civilians of Namhae, who the Chinese General Chen Lin labelled as Japanese collaborators, were killed without justification.

Legacy
The war left significant legacies in all three countries. In the context of Japanese imperialism, the invasions are seen as the first Japanese attempt to become a global power. This partial occupation of Korea developed the Japanese concept that Korea had always been part of Japan, and the Japanese leaders of the late 19th and the early 20th centuries further used the Korean invasions to justify their 20th century occupation of Korea.

In China the war was used to inspire nationalistic resistance against Japanese imperialism during the 20th century. In Chinese academia, historians list the war as one of the Wanli Emperor's "Three Great Punitive Campaigns". Contemporary Chinese historians often use the campaigns as an example of the friendship the two nations shared.

In Korea, the war is a historic foundation of Korean nationalism, and like in China, was used to inspire nationalistic resistance against Japanese imperialism during the 20th century. Korea gained several national heroes during the conflict, such as Admiral Yi., who continue to be studied. Even today, anti-Japanese sentiment in Korea can be partly traced back to the Japanese invasions in 1592, which continue to be used as a historical reference for Korean opposition to Japan.

International awareness
Despite the great interest in the war in East Asia, the Japanese invasions of Korea are not widely known in the west. Historian Stephen Turnbull attributes this ignorance to titles such as Hideyoshi's Invasions of Korea (merely an extended part of Toyotomi Hideyoshi's biography) and the Japanese invasions of Korea (simply a larger repeat of the Japanese wakō pirate raids) absent the distinction as a "war". Many history textbooks treat the war with only a few lines of mention, and with the exception of Samurai Invasion: Japan's Korean War 1592–98 by Stephen Turnbull, no complete academic studies on the subject exists in English, although both Murdoch and Sansom covered the topic in some detail in their general historical surveys of Japan, A History of Japan (1903) and A History of Japan (1958), respectively.