Japanese invasions of Korea
The Japanese landing on Busan
Date 1592–1598 Location Korean Peninsula Result Korean-Chinese victory; Withdrawal of Japanese armies
Belligerents
Korea: Joseon Dynasty China: Ming Dynasty	Japan: Azuchi-Momoyama period
Commanders and leaders
Korea Yi Sun-sin†, Yi Eok-gi†, Won Gyun†, Sin Rip†, Kim Si-min†, Song Sang-hyeon†, Go Gyeong-myeong†, Kim Cheon-il†, Jo Heon†, Gwon Yul, Yu Seong-ryong, Kim Myeong-won, Yi Il, Gwak Jae-u, Jeong Ki-ryong, Kim Deok-nyeong, Yu Jeong, Seosan, Jeong Mun-bu, Kim Chung-seon. China Song Yingchang, Yang Hao, Li Rusong, Xing Jie, Listed above: Inspectors-general/field commanders Yang Shaoxun, Ma Gui (pr.), Liu Ting, Deng Zilong†, Wu Weizhong, Chen Lin Qian Shizheng et al.	Japan Toyotomi Hideyoshi, Ukita Hideie, Katō Kiyomasa, Fukushima Masanori, Konishi Yukinaga, Kuroda Nagamasa, Mōri Terumoto, Kobayakawa Takakage, Mōri Katsunobu, Toyotomi Hidekatsu, Listed above: Legion chiefs Chōsokabe Motochika, Shimazu Yoshihiro, Tachibana Muneshige, Kobayakawa Hidekane, Kuki Yoshitaka, Tōdō Takatora, So Yoshitoshi, Wakizaka Yasuharu, Katō Yoshiaki, Kurushima Michiyuki†, Kurushima Michifusa† et al.
Strength
Korea 172,000 Korean Army,[1] (at the beginning) at least 22,600 Korean volunteers and insurgents China 1st. (1592–1593) 43,000+[2] 2nd. (1597–1598) ~75,000[3] Total:221,500[4]	Japan 1st. (1592–1593) ~ 158,000 [5] 2nd. (1597–1598) ~ 141,500[6]
Casualties and losses
Joseon: 300,000+ killed civilian + military total 260,000-1,000,000[7][8]	140,000+ killed

The two Japanese invasions of Korea took place from 1592 to 1598. Toyotomi Hideyoshi led the newly unified Japan into the first invasion (1592–1593) with the professed goal of conquering the Joseon Dynasty Korea, the Jurchens, and eventually Ming Dynasty China,^[9] and the European Merchants (Nanban,南蛮^[10][11]). The second invasion (1594–1596) was aimed as a retaliatory offensive against Joseon Dynasty Korea and Ming Dynasty China as its ally.^[9] The invasions are also known as Hideyoshi's invasions of Korea, the Seven Year War (in reference to its span), the Imjin Waeran (Hangul: 임진왜란, Hanja: 壬辰倭亂 - lit. Japanese Invasion of the Imjin Year), in reference to the "Imjin (壬辰)" year of the sexagenary cycle in Korean,^[12] and Bunroku Keichō no eki (Japanese: 文禄・慶長の役).

Name[link]

The first invasion (1592–1593) is literally called the "Japanese (倭 |wae|) Disturbance (亂 |ran|) of Imjin" (1592 being an imjin year in the sexagenary cycle) in Korean. 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. Meanwhile, the war is called Bunroku no eki in Japanese (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 was the conquest of Ming China although the armies of Toyotomi Hideyoshi were confined to the Korean Peninsula for the duration of the war.

Overview[link]

Initially, the Japanese forces saw overwhelming success on land and repeated defeat at sea due to the skill of the Korean Admiral Yi Sun-Sin. The Japanese forces came to suffer heavily as their communication and supply lines were disrupted. The Korean navy starved the Japanese forces by successfully intercepting the Japanese supply fleets on the western waters of the peninsula, to which most major rivers of the Korean peninsula flow. The Ming dynasty in China under the Wanli Emperor brought about a military and diplomatic intervention to the conflict, which China understood as a challenge to its tributary system.^[13] The war stalled for five years during which the three countries tried to negotiate a peaceful compromise. The first phase of the invasion was during the period of 1592 until 1596, with a brief interlude for, what would be failed peace negotiations between 1596 and 1597; however, Japan invaded Korea a second time in 1597. The war concluded with the naval battle at Noryang. All of the Japanese forces in Korea had retreated by the 12th lunar month of 1598 and returned to Japan after the devastating defeat dealt by the Korean Navy.

Effects[link]

Korea suffered the loss of a large portion of its population and faced gigantic financial difficulties as a result of the war taking place almost entirely on its soil and nowhere else.

In addition to the human losses, Korea suffered tremendous cultural, economic, and infrastructural damage, including a large reduction in the amount of arable land,^[12] the destruction and confiscation of significant artworks, artifacts, and historical documents, and the abductions of artisans and technicians. During this time, the main Korean royal palaces Gyeongbokgung, Changdeokgung, and Changgyeonggung were burned down, the palace Deoksugung was used as a temporary palace.^[14] 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 fall of the Ming Dynasty and the rise of the Qing Dynasty.^[15] However, the sinocentric tributary system that Ming had defended was restored by Qing, and the trade relations between Korea and Japan continued.^[16]

Background[link]

Korea and China before the war[link]

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 Joseon.^[17] 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[1] within the context of the Mandate of Heaven.^[18] Under Ashikaga Yoshimitsu's reign during the late 15th century, Japan, too, gained a seat in the tributary system (lost by 1547, see hai jin).^[19][20] Within this tributary system, China assumed the role of a big brother, Korea the middle brother, and Japan the younger brother.^[21]

Unlike the situation over one thousand years earlier when Chinese dynasties had an antagonistic relationship with the largest of the Korean polities (Goguryeo), Ming China had close trading and diplomatic relations with the Joseon Dynasty, which also enjoyed continuous trade relations with Japan.^[22]

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).^[23] 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.^[24][25] 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 several of the key issues that had plagued the Ming, including its financial problems. Zhang also made strong progress against the Mongols of the north, and promoted military generals based on their merits, such as Li Chengliang and Qi Jiguang.

Although after Zhang Juzheng's passing 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 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 Woko pirates a couple decades earlier also gave them significant experience against the Japanese style of warfare. Japan was by this time ending an period of internal conflict and the process of unification had been taken forward by Toyotomi. Japan launched the first attack to the Korean Peninsula, with the pretext that Korea refused to let pass Japanese soldiers trough their land to get to China. This could have effectively been true since, on one hand Japan was eager, for social and economic reasons, to take land into the continent and expand, also by that time China and Korea were allies.

Hideyoshi and his preparations[link]

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 necessary for the Imperial Shogun commission, he sought for military power to legitimize his rule and to decrease his dependence on the Imperial family.^[26] It is said that Hideyoshi planned an invasion of China to fulfill the dreams of his late lord Oda Nobunaga,^[27] and to mitigate the possible threat of civil disorder or rebellion posed by the large number of samurai and soldiers in unified Japan.^[28] But it is 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 ^[26] all throughout the invasion of Korea, Hideyoshi sought for legal tally trade with China^[26] Hideyoshi's need for military supremacy as a justification for his rule which lacked Shogunal background could, on an international level, translate into a Japanocentric order with Japan's neighbouring countries below Japan.^[26] Historian Kenneth M. Swope mentions a rumor circulating at the time that Hideyoshi could have been Chinese who then fled to Japan from the law, and therefore sought revenge against China.^[29] Also, another theory states that Hideyoshi needed the war to make sure no rebellion would arise in Japan against him and to debilitate some competing daimyōs by making them fight a war, away from Japanese territory.[2]. This 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^[30] finally brought about the second unification of Japan,^[31] 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) as the center for the mobilization of the invasion forces.^[32]

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 battling under Nobunaga against Mōri Terumoto for control of the Chūgoku region of Japan, informed Terumoto of Nobunaga's plan to conquer China.^[33] 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.^[34]

As for the military preparations, the construction of as many as 2,000 ships may have begun as early as 1586.^[35] To estimate the strength of the Korean military, Hideyoshi sent an assault force of 26 ships to the southern coast of Korea in 1587.^[36] 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.^[37]

Diplomatic dealings between Japan and Korea[link]

In 1587, Hideyoshi sent his first envoy Yutani Yasuhiro,^[38][39][40] to Korea, which was during the rule of King Seonjo^[41] to re-establish diplomatic relations between Korea and Japan (broken since the Japanese pirate raid in 1555),^[42] which Hideyoshi hoped to use as a foundation to induce the Korean court to join Japan in a war against China.^[43] 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.^[44]

Around May 1589, Hideyoshi's second embassy, consisting of Sō Yoshitoshi (or Yoshitomo),^[45][46] Yanagawa Shigenobu^[47][48] and Buddhist monk Genso^[49] reached Korea and secured the promise of a Korean embassy to Japan in exchange for the Korean rebels which had taken refuge in Japan.^[44]

In fact, in 1587 Hideyoshi had ordered the adopted father of Yoshitoshi and the daimyō of Tsushima, Sō Yoshishige,^[39][50] to offer Joseon the ultimatum of submitting to Japan and participating in the conquest of China, or engage 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,^[51] the Sō family delayed the talks for nearly two years.^[45] 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 Seonjo a brace of peafowl and matchlock guns - the first advanced fire-arms to come to Korea.^[52] 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 cooperate.^[53] This lack of interest and underestimation of the power of the arquebus eventually led to the decimation of the Korean army early in the war.

On April 1590, the Korean ambassadors including Hwang Yun-gil, Kim Saung-il and others^[54] left for Kyoto, where they waited for two months while Hideyoshi was finishing his campaign against the Odawara and the Hōjō clans.^[55] Upon his return, they exchanged ceremonial gifts and delivered King Seonjo's letter to Hideyoshi.^[55] 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 diplomatic matters representatives; at last, the Korean ambassadors asked for Hideyoshi to write a reply to the Korean king, for which they waited 20 days at the port of Sakai.^[56] The letter, redrafted as requested by the ambassadors on the ground since it was too discourteous, invited Korea to submit to Japan and join the war against China.^[52] Upon the ambassadors' return, the Korean court held serious discussions concerning Japan's invitation;^[57] while Hwang Yun-gil reported to the Korean court conflicting estimates of Japanese military strength and intentions and pressed that a war was coming, Kim Saung-il claimed that Hideyoshi's saying was nothing but a bluff. Moreover, most of the estimates considered the Japanese to be incompetent. Some, including King Seonjo, 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.^[58]

Hideyoshi initiated his diplomacy moves with Korea. The Joseon Court approached Japan as a country inferior to Korea accordingly within the Chinese tributary system, and it evaluated Hideyoshi's invasions to be no better than the common wakō, Japanese pirate raids.^[59] The Korean court handed to Shigenobu^[47] and Genso, Hideyoshi's third embassy, King Seonjo's letter rebuking Hideyoshi for challenging the Chinese tributary system; Hideyoshi replied with a disrespectful letter, but, since it was not presented in person as expected by custom, the Korean Court ignored it.^[60] After the denial of his second request, Hideyoshi launched his armies against Korea in 1592.

China had several reasons to involve itself in the Korea-Japanese war. Primarily China had to held its responsibility to its tributary states as was Korea at the time. If China had not gotten involved it would have seem like they were vulnerable and it could have given too much confidence to the Japanese to try and declare an open war directly to China. The other possible consequence of not getting involved and not stand up for Korea, would have been other tributary states bringing up an opposition and, by doing so the entire tributary system would have fallen apart. Of course there was also the obvious fact that this Japanese attack was a serious threat, as stated above Hideyoshi had made several declarations of his intentions to enter in China and conquest it, as he also stated of his goal to even reach India.

Military capabilities[link]

Hwacha were developed by Koreans and could shoot up to 200 arrows at one time.

Many of the castles in Korea were strong mountain fortresses like this one. Other stone fortresses, however, were of poor quality and structure.

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.^[61][62]

In response to the threats, the Koreans developed a powerful navy, constructed a thorough defense line of fortresses along the Tumen River, and took control of the island of Tsushima.^[63] This defensive stance within an environment of relative peace pushed the Koreans to depend on a heavy artillery of fortresses and warships. With the transmission of gunpowder and firearms technology from China during the Goryeo Dynasty, Korea improved upon the original Chinese designs of firearms 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 excelled in both cannon manufacturing and shipbuilding in this age.^[64]

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 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. The Korean cannons were highly effective against Japanese naval vessels, as a few effective hits would sink the ship along with its crew. On land, however, the charging Japanese infantry were very difficult targets for the Korean cannons, and the small arms carried by Japanese soldiers had greater advantage. This strategic difference in weapons development and implementation contributed to the in-war Japanese dominance on land, and the Korean dominance at sea.

As Japan had been at war since the mid-15th century, Hideyoshi had half a million battle-hardened soldiers at his disposal^[65] to form a remarquable professional army in Asia for the invasion of Korea.^[66] While Japan's chaotic state had left the Koreans with a very low estimate of Japan as a military threat,^[66] 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.^[67] 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.^[67] Ironically enough, the Koreans believed that Hideyoshi's invasion would be just an extension of the previous pirate raids that had been repelled before.^[68] 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":^[69] rise in ranks depended far more on social connections than military knowledge.^[70] Korean soldiers were disorganized, ill-trained and ill-equipped,^[70] and they were used mostly in construction projects such as building castle walls.^[71]

Problems with Joseon Defense Policies[link]

Japanese arquebuses of the Edo era. These types of firearms were used by Japanese soldiers during Hideyoshi's invasions.

There were several defects with the organization of the Joseon-era Korean military defence system.^[72] 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.^[72] This arrangement was highly inefficient since the nearby forces would remain stationary until the mobile border commander arrived on the scene and took control.^[72] 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.^[72] Finally, as a main army was never maintained, new and ill-trained recruits conscripted during war constituted a significant part of the army.^[72] 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.^[72]

The dominant form of the Korean fortresses was the "Sanseong", or the mountain fortress,^[73] which consisted of a stone wall that continued around a mountain in a serpentine fashion.^[66] 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.^[66] 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.^[66]

Troop strength[link]

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.^[74] 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.^[75]

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.^[71] During the first invasion, Joseon deployed a total of 84,500 regular troops throughout, assisted by 22,000 non-regular volunteers.^[76] Aid from the Chinese during the war could not have made up for the difference in numbers since they never maintained more than 60,000 troops in Korea at any point of the war,^[77] while the Japanese used a total of 500,000 troops throughout the entire war.^[65]

Weapons[link]

Joseon cannons such as this one were extensively used in the Joseon navy.

Large iron-tipped wooden missile fired from Korean cannons.

Since its introduction by the Portuguese traders on the island of Tanegashima in 1543,^[78] the arquebus had become widely used in Japan.^[79] 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.^[55] In contrast, the Japanese often deployed the arquebus in combination with archery in war.^[80]

Korean archers used advanced composite bows, which was made of different materials laminated together along with an inward curve to increase power. These composite bows had a maximum range of 500 yards, in comparison to the 350 yards of most standard Japanese bows.^[81]

The Chinese used a variety of weapons, including long bows,^[81] swords,^[82][83] firearms, early kind of land mines and early hand grenades.^[84]

An illustration of an ampulliform Chinese fire-lance with a gunpowder charge shooting a blast of flame with lead pellets as coviative projectiles. The weapon was called the 'phalanx-charging fire-gourd'

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 is because the Koreans, who fare fairly well in ranged combat by employing small firearms and bows, 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?"

He 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."^[85]

As for field artillery, it seems the Koreans seldom employed them, with cannons mainly used in siege action and in defending castles. However, there are a few cases of Koreans employing artillery in the field. At the battle of Haengju, the Korean army employed "Earth" class cannon (Jija-chongtong) behind field fortification. In addition, a irregular Korean units with government-supplied weapons used explosive shots fired from mortars at the open terrain in Ban-am, Gyeongsang district. This is recorded in "The Diary of a Militia" (향병일기; Hyangbyeong-ilgi), which is stored in the database of www.history.go.kr. The Chinese seem to have been more active in employing field artillery than the Koreans. One of the notable Chinese field gun was "Great General Cannon". This was a large breech-loading cannon with two-wheeled cart, shooting an iron ball weighing about 10 kilograms. The Japanese, on the other hand, employed virtually no artillery neither in siege or field warfare. (Nevertheless, when Admiral Yi bombarded Japanese base in Busan, the Japanese employed looted Korean cannon against the Korean Navy, using Korean captives.)

The Koreans actively deployed their cavalry divisions in action, however they often suffered significant disadvantages. Terrain was often mountainous, lacking both the flat plains suitable for cavalry charges, the land was prone to ditches, and it lacked grass essential in feeding their horses. In addition, Japanese use of the arquebus at long range and in concentrated volleys negated effective cavalry tactics.^[83] 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.^[86] 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),^[87] their use was reduced by increasing logistical difficulties and the increasing use of firearms by the Koreans and Chinese.^[88]

Naval power[link]

An old painting of a panokseon.

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.

As virtually all Japanese ships in the first phase of the war lacked cannon artillery,^[64] Korean ships outranged and bombarded Japanese ships with impunity outside the range of the Japanese muskets, arrows, and catapults.^[64] When the Japanese attempted to outfit cannon to their ships,^[89] their lightweight ship design prohibited using more than a few per vessel and usually lacked the firepower or range of their Korean counterparts^[90]

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.^[64][91] 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.

Admiral Yi's leadership and strategic thinking was also a large factor in Korea's naval dominance, using a superior naval force to disrupt the Japanese logistical network and hence limit the Japanese forces ability to operate inland.

In order to bolster his fleet, Hideyoshi attempted unsuccessfully to hire two Portuguese galleons to join the invasion.^[92]

First invasion (1592–1593)[link]

Initial attacks[link]

Busan and Dadaejin[link]

On May 23, 1592, the First Division of the Japanese invasion army consisting of 7,000 men led by Konishi Yukinaga^[95] left Tsushima in the morning, and arrived at the port city of Busan in the evening.^[96] 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.^[97] A later report of the arrival of an additional 100 Japanese vessels raised his suspicions, but the general did nothing about it.^[97] 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.^[96] 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.^[98]

Dongnae[link]

"Dongnaebu Sunjeoldo", a Korean painting from 1760 depicting the Battle of Dongnae.

On the morning of May 25, 1592, the First Division arrived at Dongnae eupseong.^[98] The resulting fight lasted twelve hours, killed 3,000, and resulted in Japanese victory.^[99] A popular legend describes the governor in charge of the fortress, Song Sang-hyeon. When Konishi Yukinaga again demanded before the battle that the Koreans allow the Japanese to travel through the peninsula, the governor was said to have replied, "It is easy for me to die, but difficult to let you pass."^[99] Even when the Japanese troops neared his commanding post during the battle, Song remained seated with cool dignity.^[99] Finally, when a Japanese soldier cut off Song's right arm holding his staff of command, Song picked up the staff with his left arm, which was then cut off; again Song picked it up, this time with his mouth, but was killed by a third blow.^[99] The Japanese, impressed by Song's defiance, treated his body with proper burial ceremony.^[99]

Occupation of the Gyeongsang Province[link]

Katō Kiyomasa's Second Division landed in Busan on May 27, and Kuroda Nagamasa's Third Division, west of Nakdong, on May 28.^[100] The Second Division took the abandoned city of Tongdo on May 28, and captured Kyongju on May 30.^[100] 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.^[101] By June 3, the Third Division captured Unsan, Changnyong, Hyonpung, and Songju.^[101] Meanwhile, Konishi Yukinaga's First Division passed the Yangsan mountain fortress (captured on the night of the Battle of Dongnae, when its defenders fled when the Japanese scouting parties fired their arquebuses), and captured the Miryang castle on the afternoon of May 26.^[102] The First Division secured the Cheongdo fortress in the next few days, and destroyed the city of Daegu.^[102] By June 3, the First Division crossed the Nakdong River, and stopped at the Sonsan mountain.^[102]

Joseon response[link]

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.^[103] 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.^[102] There, General Yi moved all troops back to Sangju, except for the survivors of the Battle of Dongnae who were to be stationed as a rearguard at the Choryong pass.^[102]

Battle of Sangju[link]

On April 25,^[104] General Yi deployed a force of less than 1,000 men on two small hills to face the approaching First Division.^[105] 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.^[105] The Korean troops, watching him fall, were greatly demoralized.^[105] Soon the Japanese began the battle with their arquebuses; the Koreans replied with their arrows, which fell short of their targets.^[105] 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.^[105]

Battle of Chungju[link]

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.^[105] However, another commander, Sin Rip, appointed by the Joseon government had arrived in the area with a cavalry division, and moved 8,000 combined troops to the Chungju fortress, located above the Choryong pass.^[106] General Sin Rip then wanted to fight a battle on an open field, which he felt ideal for the deployment of his cavalry unit, and placed his units on the open fields of Tangeumdae.^[106] As the general feared that, since the cavalry consisted mostly of new recruits, his troops would flee in battle easily,^[107] 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".^[106] However, the field was dotted with flooded rice paddies, and was not suitable for cavalry action.^[106]

On June 5, 1592 the First Division of 18,000 men^[107] led by Konishi Yukinaga left Sangju, and reached an abandoned fortress at Mungyong by night.^[108] 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 and the front.^[108] The Korean arrows fell short of the Japanese troops, which were outside their range, and General Sin led two charges that failed against 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.^[108]

Capture of Seoul[link]

The Second Division led by Katō Kiyomasa arrived at Chungju, with the Third Division not far behind.^[109] There, Katō expressed his anger against Konishi for not waiting at Busan as planned, and attempting to take all of the glory for himself; then Nabeshima Naoshige 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.^[109] 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.^[109] Konishi arrived at Hanseong first on June 10 while the Second Division was halted at the river with no boats with which to cross.^[109] The First Division found the castle undefended with its gates tightly locked, as King Seonjo had fled the day before.^[110] The Japanese broke into a small floodgate, located in the castle wall, and opened the capital city's gate from within.^[110] 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.^[110] Meanwhile, the Fifth, Sixth, Seventh, and Eighth Divisions had landed on Busan, with the Ninth Division kept in reserve on the island of Iki.^[110]

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.^[110] General Kim Myong-won, in charge of the defenses along the Han River, had retreated.^[111] The King's subjects stole the animals in the royal stables and fled before him, leaving the King to rely on farm animals.^[111] 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.^[111] 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.^[111]

Japanese campaigns in the north[link]

Crossing of the Imjin River[link]

While the First Division rested in Hanseong, the Second Division began heading north, only to be delayed by the Imjin River for two weeks.^[111] 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.^[111] Then 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.^[111] The main Japanese body retaliated against the isolated Korean troops, and acquired their boats; at this, the Korean General Kim Myong-won retreated with his forces to the Kaesong fortress.^[112]

Distribution of Japanese forces in 1592[link]

With the Kaesong castle having been sacked shortly after General Kim Myong-won retreated to Pyeongyang,^[112] 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).^[113]

Capture of Pyeongyang[link]

The First Division under Konishi Yukinaga proceeded northward, and sacked Pyongsan, Sohung, Pungsan, Hwangju, and Chunghwa on the way.^[114] At Chunghwa, the Third Division under Kuroda Nagamasa joined the First, and continued to the city of Pyeongyang located behind the Taedong River.^[114] 10,000 Korean troops guarded the city against 30,000 Japanese ^[115] 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.^[114]

On the night of July 22, 1592, the Koreans silently crossed the river and launched a successful surprise attack against the Japanese encampment.^[114] However, this stirred up the rest of the Japanese army, which attacked the rear of the Korean positions and destroyed the reinforcements crossing the river.^[116] Then the rest of the Korean troops retreated back to Pyeongyang, and the Japanese troops gave up their pursuit of the Koreans to observe the way the Koreans crossed the river.^[116]

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.^[117] On July 24, the First and Third Divisions entered the deserted city of Pyeongyang.^[117]

Campaigns in the Gangwon Province[link]

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.^[117] The division then turned inward to capture Jeongseon, Yeongwol, and Pyeongchang, and settled down at the provincial capital of Wonju.^[117] There Mōri Yoshinari established a civil administration, systematized social ranks according to the Japanese model, and conducted land surveys.^[117] 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.^[118]

Campaigns in the Hamgyong Province and Manchuria[link]

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.^[118] 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.^[119]

The rest of the division of 10,000 men^[115] 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).^[119] A Korean cavalry division took advantage of the open field at Songjin, and pushed the Japanese forces into a grain storehouse.^[119] There the Japanese barricaded themselves with bales of rice, and successfully repelled a formation charge from the Korean forces with their arquebuses.^[119] 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.^[119] Here, those that fled were trapped and slaughtered.^[119]

Koreans who fled gave alarms to the other garrisons, allowing the Japanese troops easily to capture Kilchu, Myongchon, and Kyongsong.^[119] The Second Division then turned inland through Puryong toward Hoeryong where two Korean princes had taken refuge.^[119] 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.^[119] 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.^[119]

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).^[120] 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.^[120] 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.^[120] Despite having the advantage, Katō Kiyomasa retreated with his forces to avoid heavy losses.^[120] 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.^[120] There the Japanese rested on the beach, and watched a nearby volcanic island rising on the horizon that they mistook as Mount Fuji.^[120] 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.^[121]

Naval battles of Admiral Yi[link]

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.^[122] 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.^[122] Thus the Japanese, now lacking enough arms and troops to carry on the invasion of the Jurchens, changed the objective of the war to the occupation of Korea.^[122]

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.^[97] Won Gyun, the Right Naval Commander, also destroyed and abandoned his own base, and fled to Konyang with only four ships.^[97] 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.^[97] Admiral Won later sent a message to Admiral Yi that he had fled to Konyang after being overwhelmed by the Japanese in a fight.^[123] 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.^[123] 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.^[123]

Admiral Yi's battles greatly affected the war and put significant strain on Japanese supply routes.^[124]

Battle of Okpo[link]

Admiral Yi relied on a network of local fishermen and scouting boats to receive intelligence of the enemy movements.^[124] 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.^[124] 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^[125] then began circumnavigating the Geoje Island, bound for the Gadeok Island, but scouting vessels detected 50 Japanese vessels at the Okpo harbor.^[124] 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.^[124] At this, the Korean fleet encircled the Japanese ships and finished them with artillery bombardments.^[126] The Koreans spotted five more Japanese vessels that night, and managed to destroy four.^[126] The next day, the Koreans approached 13 Japanese ships at Jeokjinpo as reported by the intelligence.^[126] 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.^[126]

A turtle ship replica at the War Memorial in Seoul. The historical existence of the ironclad roof is disputed.^{[127][128][129]}

Battle of Sacheon and the Turtle Ship[link]

About three weeks after the Battle of Okpo,^[130] 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.^[131] 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.^[130]

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^{[127][128][129]}).^[132] 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.^[131] This design also prevented the outsiders from boarding the ship and aiming at the personnel inside.^[132] 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.^[91] 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.^[91]

On July 8, 1592, the fleet arrived at the Bay of Sacheon, where the outgoing tide prevented the Korean fleet from entering.^[130] Therefore, Admiral Yi ordered the fleet to feign withdrawal, which the Japanese commander observed from his tent on a rock.^[132] Then the Japanese hurriedly embarked their 12 ships and pursued the Korean fleet.^[130] The Korean navy counterattacked, with the Turtle Ship in the front, and successfully destroyed all 12 ships.^[130] Admiral Yi was shot by a bullet in his left shoulder, but survived.^[130]

Battle of Dangpo[link]

On July 10, 1592, the Korean fleet again found and destroyed 21 Japanese ships, which were anchored at Dangpo while the Japanese raided a coastal town.^[133]

Battle of Danghangpo[link]

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.^[133] 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.^[133] Having traveled through a narrow gulf, the Koreans sighted a total of 26 enemy vessels in the bay.^[133] The turtle ship was used to penetrate the enemy formation and rammed the flagship, while the rest of the Korean fleet held back.^[134] Then Admiral Yi ordered a fake retreat, as the Japanese could escape to land while in the bay.^[134] When the Japanese 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 were unable to counter the Korean cannon.^[134] Only 1 Japanese ship managed to escape from this route, and that too was caught and destroyed by a Korean ship the next morning.^[134]

Admiral Yi's crane wing formation, famously used at the Battle of Hansando.

Battle of Yulpo[link]

On July 15, the Korean fleet was sailing east to return to the island of Gadok, and successfully intercepted and destroyed seven Japanese ships coming out from the Yulpo harbor.^[134]

Battle of Hansando[link]

In response to the Korean navy's success, Toyotomi Hideyoshi recalled three admirals from land-based activities: Wakizaka Yasuharu, Kato Yoshiaki, and Kuki Yoshitaka.^[134] They were the only ones with naval responsibilities in the entirety of the Japanese invasion forces.^[134] However, the admirals arrived in Busan nine days before Hideyoshi's order was actually issued, and assembled a squadron to counter the Korean navy.^[134] Eventually Admiral 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 admirals to finish.^[134]

The combined Korean navy of 70 ships^[135] 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.^[134] The Jeolla Province was the only Korean territory to be untouched by a major military action, and served as home for the three admirals and the only active Korean naval force.^[134] The admirals considered it best to destroy naval support for the Japanese to reduce the effectiveness of the enemy ground troops.^[134]

On August 13, 1592, the Korean fleet sailing from the Miruk Island at Dangpo received local intelligence that a large Japanese fleet was nearby.^[134] The following morning, the Korean fleet spotted the Japanese fleet of 82 vessels anchored in the straits of Gyeonnaeryang.^[134] 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,^[135] and the Japanese fleet followed.^[134] There the Japanese fleet was surrounded by the Korean fleet in a semicircular formation called "crane wing" by Admiral Yi.^[134] 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.^[134] 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.^[134] The battle ended in a Korean victory, with Japanese losses of 59 ships – 47 destroyed and 12 captured.^[136] Several Korean prisoners of war were rescued by the Korean soldiers throughout the fight. Admiral Wakisaka escaped due to the speed of his flag ship.^[136] 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.^[134]

Battle of Angolpo[link]

On August 16, 1592, Yi Sun-sin led their fleet to the harbor of Angolpo where 42 Japanese vessels were docked.^[134] 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.^[134] 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.^[134]

Korean Militias[link]

From the beginning of the war, the Koreans organized militias called the "Righteous Army" (의병) to resist the Japanese invasion.^[137] These fighting bands were raised throughout the country, and participated in battles, guerilla raids, sieges, and the transportation and construction of wartime necessities.^[138]

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.^[138]

During the first invasion, the Jeolla Province remained the only untouched area on the Korean peninsula.^[138] In addition to the successful patrols of the sea by Admiral Yi, volunteer activism pressured the Japanese troops to avoid the province for other priorities.^[138]

Gwak Jae-u's Campaigns along the Nakdong River[link]

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.^[139] 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^[138] and an attack seemed imminent, Gwak organized fifty townsmen; however the Third Division went from Changwon straight toward Songju.^[139] 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.^[139] 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.^[139] 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.^[139]

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.^[139] This strategy prevented easy access for the Japanese troops to the Jeolla Province where Admiral Yi and his fleet were stationed.^[139]

Battle of Uiryong/Chongjin[link]

The Sixth Division under the command of Kobayakawa Takakage was in charge of conquering the Jeolla Province.^[139] 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.^[139]

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.^[139] 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.^[139] As the Japanese troops began to cross, Gwak's militia ambushed them, and caused heavy losses for the Japanese.^[139] 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.^[139] At Kaenyong, Ankokuji's target was changed to Gochang, to be taken with the aid of Kobayakawa Takakage.^[139] 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.^[139]

Jeolla coalition and Battle of Yong-in[link]

When the Japanese troops were advancing to Hanseong (present-day Seoul), Yi Kwang, the governor of the Jeolla Province, attempted to check the Japanese progress by launching his army toward the capital city.^[140] Upon hearing the news that the capital had already been sacked, the governor withdrew his army.^[140] 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.^[140][141] 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.^[140][142] The Japanese troops counterattacked successfully against the Jeolla coalition, forcing the Koreans to abandon arms and retreat.^[140]

First Geumsan Campaign[link]

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.^[140] 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.^[140] Having joined forces with General Gwak Yong, Go then led his soldiers to Geumsan.^[140] 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^[143]

Siege of Jinju[link]

Jinju (진주) was a strategic stronghold that defended Kyonhsang 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 Si-min (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. Hosokawa lost over 30,000 men. The battle at Jinju is considered one of the greatest victories of Korea because it prevented the Japanese from entering Jeolla.

Intervention of Ming China[link]

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, had to rely on an external factor, the intervention of Ming China, to foil the first Japanese invasion.^[144]

Korean Court historian Yu Song-nyong stated that the Korean naval victory spoiled 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.^[144]

Ming Dynasty Wanli Emperor      萬曆神宗皇帝

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 overran so quickly.^[145] This, combined with the fact that they were still dealing with a military rebellion in Ningxia, resulted in a slow response.

The Korean Court was at first hesitant to call for help from the Ming Dynasty ^[146] The local governor at Liaodong eventually acted upon King Seonjo's request for aid by sending a small force of 5,000 soldiers led by Zu Chengxun. This cavalry force advanced almost unhindered and even entered Pyongyang, where they were badly defeated by the Japanese troops in the streets. One of their main generals, Shi Ru, was killed in this engagement. During the later half of 1592, the Ming also sent investigation teams into Korea to clarify the situation.^[147] 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). The army had a prescribed strength of 100,000, though actual strength was much lower. According to the collection of letters left by Song Yingchang, the actual strength of the Ming army that crossed into Korea in late 1592 was 36,000 - eventually reinforced to over 38,000 by early February -^[148] composed mostly of garrisons from the north, including 3,000+ men who were trained by officers with experience against Japan-based pirates a couple decades prior under Qi Jiguang and other generals.

Ming Army's matchlocks, an early muzzle-loaded firearm used in the 15th to 17th centuries,.

Siege of Pyongyang[link]

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 armies in Korea. After initial attempts to negotiate with the Japanese defenders under Konishi Yukinaga broke down,^[149] the two sides began skirmishing on the outskirts over the next couple of days, with the allied forces attempting to dislodge a Japanese garrison on the hills north of the city while the Japanese attempted a night raid on the Ming camp.^[149]

On the morning of the 8th, Li ordered an all-out assault on 3 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.^{[150][151][152]}

Battle of Byeokjegwan[link]

Soon after retaking Pyongyang, the allied forces also succeeded in retaking the major city of Kaesong on 19 January ^[153] and met only minor resistance from the Japanese defenders.

Overconfident with his recent success and possibly misled by false reports,^[154] 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.^[155]

Battle of Haengju[link]

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[link]

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

The two sides remained at stalemate between the Kaesong to Seoul line for the next couple of months, 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, these conflicts would eventually have further implications in the events of Japan following the war. (see Battle of Sekigahara)

The Allied forces on the other hand, was 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 one such general ( Qian ShiZheng) 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,^[156] 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.^[157]

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, but their desire to reclaim their country along with the militarily inexperienced nature of many of their administrators resulted in them continuing requesting the Ming forces to advance despite the situation. These events created an increasing level of distrust between the two sides.

The Ming forces also had some internal conflicts, as the forces with Southern China origins were often at odds with Li Rusong and his northmens, Qian ShiZheng in his records noted that the Northmen often did not follow orders and stole their gains in battles. While Li also appeared to have favored his compatriots more than the forces from southern China.

Though by mid April 1593, faced with ever greater logistical pressure from blockade of Admiral Yi and the Righteous army's raid, in addition to the Ming forces special operation that managed to burn down a very significant portion of the Japanese grain storage ^[158] the Japanese decided break off into talks and pull out of Seoul.

Negotiations and truce between China and Japan (1594–1596)[link]

Ming Army in Ningxia.

There are two things that encourage the Japanese to leave, 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 threatended the Japanese with an attack by 400,000 Chinese. The Japanese, aware of their weak situation, Konishi and Kato agreed the Japanese would withdraw to the Pusan area while the Chinese would withdraw back to China; a Ming embassy was be sent to Japan to discuss peace terms.^[159]

Hideyoshi proposed to China the division of Korea: the north as a self-governing Chinese satellite, and the south would remain in Japanese hands. The peace talks were mostly carried out by Konishi Yukinaga, who did most of the fighting against the Chinese. The offer was taken into consideration until Hideyoshi also demanded one of the Chinese princesses to be sent as his concubine. Then the offer was promptly rejected.

By May 18, 1593, all the Japanese soldiers had retreated to the area around Busan and many began to make their way back to Japan. In the summer of 1593, a Chinese delegation visited Japan and stayed at the court of Hideyoshi for more than a month. The Ming government withdrew most of its expeditionary force, but kept 16,000 men on the Korean peninsula to guard the truce.

An envoy from Hideyoshi reached Beijing in 1594. Most of the Japanese army had left Korea by the autumn of 1596; a small garrison nevertheless remained in Busan. Satisfied with the Japanese overtures, the imperial court in Beijing dispatched an embassy to allow Hideyoshi to have the title of "King of Japan" under the condition of complete withdrawal of Japanese forces from Korea.

Later, Hideyoshi abrogated a negotiation one-sidedly. Peace negotiations soon broke down and the war entered its second phase when Hideyoshi sent another invasion force. Early in 1597, both sides resumed hostilities.

Korean military reorganization[link]

Proposal for military reforms[link]

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[link]

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)[link]

Hideyoshi was dissatisfied with the first campaign and decided to attack Korea again. One of the main differences between the first and second invasions was that conquering China was no longer a goal for the Japanese. Failing to gain a foothold during Katō Kiyomasa's Chinese campaign and the full retreat of the Japanese during the first invasion affected Japanese morale.

Soon after the Chinese ambassadors returned safely to China in 1597, Hideyoshi sent 200 ships with approximately 141,100 men^[160] under the overall command of Kobayakawa Hideaki.^[67] Japan's second force arrived unopposed on the southern coast of Gyeongsang Province in 1596. However, the Japanese found that Korea was both better equipped and ready to deal with an invasion this time.^[161] In addition, upon hearing this 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^[160] from various (and sometimes remote) provinces across China, such as Sichuan, Zhejiang, Huguang, Fujian, and Guangdong.^[162] A naval force of 21,000 was included in the effort.^[163] 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.^[164] Korean forces totaled 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.^[160]

Initial offensive[link]

Initially the Japanese found little success, being confined mainly to Gyeongsang Province and only managing numerous short-range attacks as they found that the Korean defenders were much better prepared this time around.^[161] Aside from a brief period in the early Autumn of 97, Japan would mainly be on the defensive and locked in at Gyeongsang province.^[161] 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 saved this area from further 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 against Admiral Yi[link]

A naval battle. Close combat was very rare during Admiral Yi's operations.

The Korean navy played a crucial part in the second invasion, as in the first. The Japanese advances were halted due to the lack of reinforcements and supplies as the naval victories of the Korean navy prevented the Japanese from accessing the south-western side of the Korean peninsula.^[165] Also, during the second invasion, China sent a large number of Chinese ships to aid the Koreans. This made the Korean navy an even bigger threat to the Japanese, since they had to fight a larger enemy fleet.

Initially, Korea was setback in the naval arena when Won Gyun took Admiral Yi's place as commander.

Because Admiral Yi, the commander of the Korean navy, was also experienced in land warfare, the Japanese plotted to demote him by making use of the laws that governed the Korean military. A Japanese double agent working for the Koreans falsely reported that Japanese General Katō Kiyomasa would be coming on a certain date with a great Japanese fleet in another attack on Korean shores, and insisted that Admiral Yi be sent to lay an ambush.^[166]