Joseon Navy

The Joseon Navy (조선 수군; Hanja: 朝鮮水軍) was the navy of the Korean dynasty of Joseon. While originally commissioned to protect merchant vessels and coastal towns from Japanese pirate raids, the Joseon navy is best known for defeating the Japanese naval forces during the Imjin War and is often credited with halting the Japanese invasion campaign and saving the dynasty from conquest.

History
Throughout Korea's naval history, rough waters around Korea's coast usually change tides and currents. Korean shipbuilding tradition centered on creating simple but structurally sound vessels that emphasized strength and power rather than speed. The Joseon Navy utilized warships from the Goryeo Dynasty to defend against the Wokou Piracy. In the 15th century, under the decree of King Sejong, more powerful cannons were developed and tested. The cannons on battleships proved to be a great success during actions against Japanese pirate ships.

In 1419, King Sejong sent Yi Jongmu to raid the Japanese on Tsushima Island in the Oei Invasion as a response to Japanese Wokou raids on Korean coastal cities. Yi took 227 Korean ships and approximately 17,000 soldiers, landed, attacked, and plundered Japanese pirate settlements on Tsushima Island. The So clan, the ruling family of Tsushima, requested negotiations. In the diplomatic exchanges that followed, Korea permitted the So clan to continue trade with Korean coastal harbors under the condition that they suppress the activities of Japanese pirates.

During the Joseon Dynasty, the navy and maritime operations fell into disuse, while fishing vessels continued to operate and prosper. The entire military was ignored and weakened because of the relative peace during the Joseon dynasty. Also, with the policy of Korean kings that emphasized agriculture and Confucian ideals, the Korean navy, along with the rest of the Korean military, weakened steadily. However, Korea eventually developed strong wooden ships called that made up the backbone of the Joseon navy. and the Korean navy were most widely used during the Japanese invasions of Korea (1592-1598), particularly under the leadership of Admiral Yi Sun-sin. Admiral Yi also developed the turtle ship, based upon an older design. The Kobukson, or Turtle Ship, was the world's first armor-plated warship.

By the end of the 19th century, the Joseon Navy had no significant naval force other than coast defense fortresses. In March 1893, the Korean Imperial Naval Academy (통제영학당,統制營學堂) was established. The academy produces approximately 160 officers before its close during and after the First Sino-Japanese War.

Organization
In the early Joseon period, each port had a naval commander (水軍都節制使), a deputy naval commander (水軍都僉節制使), and a naval administrator (水軍處置使). During King Sejong's reign, the naval commander was renamed to naval pacification administrator (水軍都安撫處置使) and was assisted by high-ranking officers such as Domanho (都萬戶) and Manho (萬戶). According to the 『Gyeongguk Daejeon』, under the garrison system, naval commanders were stationed in major garrisons, deputy naval commanders in large garrisons, and Manho in various garrisons.

The command system of the naval forces was that one or two provincial commanders from each province commanded a provincial naval base, and each coastal county and city had a naval commander. The majority of the Joseon Navy was stationed in Gyeongsang, Jeolla, and Chungcheong provinces. After several reorganizations concerning the naval command of the military magistrates during the reign of King Sejong, he established the naval commander system, under which the naval commanders were placed.

During the reign of King Sejong, the naval forces were systematically organized in terms of the number of troops, military ships, and the establishment of forts at various ports. The naval forces and the regular army were the main conscripted forces among the civilian population. During the reign of King Seongjong in 1475, out of a total of 148,849 soldiers, the naval forces numbered 48,800, and the regular army numbered 72,109. The naval forces were supplemented not only by coastal residents but also by people from inland regions. Among the naval forces, positions such as Jinmu (鎭撫), Jiin (知印), Yeongsa (令史), Sagwan (射官), and Yeongseondumok (領船頭目) were given preferential treatment over lower-ranking soldiers.

According to the 『Gyeongguk Daejeon』, military ships were classified and distributed into large, medium, and small fierce ships (大中小猛船) for each port in each province. The total number of military ships nationwide was 737, including 81 large fierce ships, 195 medium fierce ships, and 461 small fierce ships. The crew size for each type of ship was 80 for large fierce ships, 60 for medium fierce ships, and 30 for small fierce ships. Excluding non-military ships, the total crew size multiplied by the number of ships equaled 24,400, which matched half of the total number of naval forces (48,800), aligning with the two-shift rotation system.

Ranks
In the early days of the Joseon Dynasty, the officers of the navy consisted of naval commanders of the three provinces and naval commanders in each maritime camp. A ship's crew comprises rowers, gunners, sailors, low-ranking officers, lieutenants, and a captain.

Duties
The rotation system for the naval forces was '2 rotations per month' (二番一朔相遞), with six months of service per year, whereas the regular army had '8 rotations per two months' (八番二朔相遞), with three months of service per year. Thus, the naval forces bore a heavier burden than the regular army. Initially, naval service could be alternated between the head of a household and a subordinate. Still, regulations were tightened so that only the head of a household could serve, and a wooden plaque (漆圓木牌) was used to prevent substitutes.

When reporting for duty, naval forces carried their own provisions and served on ships, being mobilized for various tasks such as garrison farming, fishing, salt production, harvesting marine products, repairing military ships, transporting goods, and building fortifications. Additionally, they were responsible for labor service, tribute goods, and special contributions. Much of the tribute from seaside regions was seafood. Salt was popular across the nation. They produce salt and capture seafood during their military service. Therefore, the role of the navy was twice as heavy as the institutional burden compared to the army.

Conditions
Originally, naval forces were supposed to serve at sea, but due to the management of military ships and arduous training, fortresses were established in the garrisons during King Seongjong's time. This shift from sea to land service blurred the distinction between naval forces and the regular army. Consequently, during King Jungjong's reign, the argument for strengthening the land forces (防倭陸戰論) emerged, advocating for the enhancement of the army's cavalry, as Korea excelled in land battles while Japan excelled in sea battles.

During the mid-Joseon period, the navy grappled with deteriorating working conditions and struggled to defend itself in confrontations. The warships of that era were highly susceptible to the whims of wind and waves. Commanders, marines, and sailors often found themselves at the mercy of power-based irregularities and mistreatment. They were also vulnerable to various diseases and contagions, leading some to desert their posts.

From King Seongjong's time, the practice of hiring substitutes and paying fees to avoid military service became common, transforming the heavy burden of naval service into a financial burden for hiring substitutes, such as the practice of collecting cloth instead of military service (방군수포, 放軍收布). Wealthy sailors and officers hired substitutes to fulfill their military duties. At the same time, officers such as Assistant Commanders (첨사, 僉使) and Commanders (만호) took clothes from sailors in exchange for exempting them from service. Additionally, people of unclear status (양천불명자, 良賤不明者) and criminals were conscripted into the navy, causing the naval service to become a low-status duty. Such circumstances have continued for over 100 years.

The government, recognizing the heavy burden of naval service, granted naval personnel honorary titles (수직, 授職), tax exemptions, exempted them from labor duties (복호, 復戶), and allowed them to live with their families. However, as naval service became less desirable, only the lower classes among civilians were conscripted into the navy. The general population was reluctant to join the navy. Consequently, during King Seongjong's reign, naval service became hereditary (세전, 世傳) to maintain a consistent number of maritime personnel. However, this accelerated the degradation of the marine service, which eventually became regarded as one of the seven low-status occupations (칠반천역, 七般賤役) in the later period.

Reforms
Admiral Yi Sun-sin prepared for the Japanese invasion of Korea in 1592. He and his subordinate Jeong Woon reformed the navy by reducing the hours of fatigue duty or banning nighttime fatigue duty. When Admiral Yi Sun-sin inspected troops and pointed to defects, commanders explained their struggles that people were tired and there were not enough supplies and capacity and lacked military power. During the Imjin War (1592, the 25th year of King Seonjo's reign), the army suffered repeated defeats. Still, the naval forces under Admiral Yi Sun-sin of Jeolla Province won numerous victories, securing control of the sea and significantly impacting the war's outcome. Admiral Yi's success in naval battles was due not only to his knowledge of the sea and the use of turtle ships but also to the superiority of large cannons (such as Seungja Choeongtong) fired from the ships.

Due to a shortage of naval forces in the late Joseon period, King Sukjong implemented the Naval Consolidation Law (水軍束伍法) to strengthen the navy. This law mixed civilians and low-status individuals, changing the previous two-shift system to a three-shift one, easing the service period.

Border Defense Council of Joseon
The Border Defense Council of Joseon was a supreme administrative organ established by the central government after the Disturbance of the Three Ports. It allowed the higher military officers, the Jibyeonsa Jaesang, to participate in the process of establishing security maneuvers to meticulously keep a keen eye on the issues of the border. Accordingly, the council applied naval security measures to Gyeongsang province and extended them to Jeolla and to the rest of the southern regions. '''

Tongjeongyeong
In 1593, during the Imjin War, the Naval Headquarters (Tongjeongyeong ) was a naval office that commanded the naval forces in Gyeongsang, Jeolla, and Chungcheong to strengthen the defense of the southern coast by placing the naval forces of Gyeongsang, Jeolla, and Chungcheong Provinces under the command of a Naval Commander (統制使). During the wars with Japan and the Later Jin, large-scale joint training exercises, known as Sujo (水操), were conducted. In the late Joseon period, Sujo was divided into provincial naval training (道水操), overseen by provincial naval commanders, and joint training (合操), overseen by the Naval Commander and the Naval Administrator. Provincial naval training involved various garrisons and ports conducting necessary training for naval battles.

Tongeoyeong
In 1627 (the 5th year of King Injo), when facing war with the Later Jin (後金), the Naval Headquarters (Tongeoyeong ) was placed in Ganghwa to lead the naval forces in Gyeonggi and Yellow Seas to defend the capital area to administer naval joint-training camps (Hapjo, ) which is supervised by each provincial monk (suba, . The naval drills (dosujo, required sailors and marines under training officers to conduct maritime training necessary for naval battles. They also became involved in the joint training of the Naval Commander, training the naval forces of Gyeongsang, Jeolla, and Chungcheong Provinces, and the Naval Administrator training the naval forces of Gyeonggi and Hwanghae Provinces according to naval training regulations. There were spring exercises (春操) in February and autumn exercises (秋操) in August, with spring exercises training to sail ships in these seasonal tides being joint training and autumn exercises being provincial training.

Defense Systems
Japanese pirate invasions intensified as the naval forces weakened due to this shift. After the Three Ports Incident (三浦倭亂), the joint defense system initially implemented only for the Gyeongsang naval forces was expanded to Jeolla Province, eventually leading to the adoption of the Jeeseungbangryak (制勝方略) defense strategy for both the navy and the army. The garrison system was a regional defense system based on provinces. At the same time, the Jeeseungbangryak involved commanders leading their troops from the main garrison to designated defense areas for combat during emergencies.

Jingwan System
The Jingwan System was a provincial defense system that dates back to the Goryeo Dynasty, building fortresses in strategically important places. Still, it leaves some parts of the nations open to invasion, and if one falls, it will be catastrophic in any war. In 1457 A.D, King Sejo reshuffled the defense system to secure as many defensive fortresses as possible to enhance the defensive depth. It comprises a Jujin, the main fortress commanded by a Jeoldosa, a provincial naval commander who takes a regional coastal defense and orders lower unit commanders. A Geojin is a medium-size local administrative unit near the coasts commanded by a Cheomjeoljesa, a county commander between the provincial capital and small local towns near the coasts called Jejins, who are commanded by the chief local magistrates or a Manho, a naval commander. Using this strategic composition, a Jingwan fights and defend their provinces, and every province has several independent Jingwans. Under this system, the roles of local commanders were to be stationed at their post, know the local topography inside and out, draft the operation plan, train local sailors and marines, and defend their defensive quarter by mobilizing their sailors and ships in the case of conflict. Originally, the naval forces were supposed to work at sea, but because of the management of the ships and the arduous training, King Seongjong installed coastal fortresses. However, when there's a massive invasion, there are not enough soldiers to defend their provinces as it was also a dispersed-force defense system. It requires the concentrated use of forced local forces to defend their defense perimeters, and the Bupiljeoktajinjijobeob rule prevents provinces from coming to each other's aid. They requested military commanders from the central government for support who did not know a familiar province's terrain.

Jeseungbangryak system
Joseon navy mobilizes its troops and ships through the Jeseungbangryak system. It allowed the military commanders from the central government to control assembled troops from the main army to the local and provincial armies. However, an admiral appointed by the king's court arrived with a newly mobilized army. It was a highly inefficient arrangement since the nearby forces would remain stationary until the mobile border commander arrived on the scene and took control. Secondly, the appointed admiral often came from an outside region. The admiral was unlikely unfamiliar with the natural environment, the available technology, and staffing of the invaded region. Finally, as the government never maintained the main army, new and ill-trained recruits conscripted during war constituted a significant part of the army.

Sogo System
Seonjo established the Sogo System in 1593, a militia system during the Imjin war based on the Ming Chinese militia system and military texts. The Sogo system required all able-bodied males to serve in the military for a certain period of time. During the reign of King Sukjong, he implemented the Sogo system to strengthen the naval forces. This system provided a steady stream of manpower for the Joseon Navy, which was able to maintain a large standing fleet capable of defending the country's coastal waters. The Sogo system also provided a means of training and equipping sailors and naval officers, ensuring that the navy was always ready for action. He reduced the service period by dividing 6-months of service into three shifts from the previous two shifts and allowing officers to alternate their duties.

Garrison Command system
The Garrison Command system was a military organization system that divided the country into military districts, with each district under the command of a garrison commander. These commanders were responsible for maintaining the readiness of their troops, ensuring that they were trained and equipped to defend against any potential threats. The Garrison Command system also facilitated the rapid deployment of troops to any part of the country, allowing the navy to quickly respond to any invasion or attack.

Ships
The most important equipment for the naval forces was military ships. Initially, there were separate ships for naval battles and transportation. According to the 『Sejong Sillok』 "Geography Section," various types of military ships were mentioned, such as large ships (大船), medium ships (中船), fast ships (快船), fierce ships (猛船), Japanese ships (倭別船), medium fierce ships (中猛船), pursuit ships (追倭別猛船), and special ships (別船), but there were no records of their shapes or sizes. During King Sejo's reign, a new type of military ship that could be used for both battles and transportation was tested, leading to the establishment of the fierce ship system (猛船制).

These ships are made of two types of wood: pine (later timber) for the hull and oak for the pegs and masts. They each had two masts and sails and were propelled by 8 to 10 oars on each side for maneuvering and increased speed. The ships had two to three levels stacked up on top of each other with u-shaped hulls that could turn them on their radius to fire on all four sides. Their flat keel enables a ship to sit comfortably on the tideland when the tide is out, after coming ashore, or inside a pier in high water. It also ensured greater mobility and a shallow draft and, in particular, allowed a ship to make sharp changes of direction at short notice. They also used smaller ships and boats for reconnaissance, skirmishes, transport, and fireships. These ships were meant to keep the Wako Pirates and the Japanese at bay and became a powerful force during the Joseon Dynasty.

During King Myeongjong's reign, the development of the panokseon (板屋船) enabled the navy to dominate the Japanese naval forces during the Imjin War with panokseon and turtle ships (龜船). Turtle ships, already in use since the early Joseon period, were modified during the Imjin War with an arched deck, creating the distinctive turtle shape. Subsequently, the naval fleet was composed of large warships (戰船) and turtle ships, medium warships (防船) and combat ships (兵船), and small warships (伺候船).

Byeongjoseon
The byeongjoseon was a warship developed during King Sejo's era during peacetime. It was a very traditional ship developed to emphasize the standard use of warships for maintaining peace on the coasts when the navy became useless after the end of King Sejong. The Byeongjoseon developed into three sizes, the daebyeongjoseon, jungbyeongjoseon, and sobyeongjoseon. The daebyeongjoseon carries 50-60 sailors and 800 lbs of grain. The jungbyeongjoseon carried 50 men, and the sobyeongjoseon carried 30 men. These ships fell into disuse as the navy developed more efficient warships.

Maengseon
The Maengseon was a warship succeeding the Byeongjoseon, serving from the time of King Seongjong to King Myeongjong. It has an appropriate number of oars installed on both sides as a place to row, and a deck is laid for soldiers to ride and engage in battle. The Maengseon came in three sizes, the Daemaengseon, Jungmaengseon, and Somaengseon deployed to naval bases. The Daemaengseon was large enough to accommodate 80 sailors, and when used as a merchant ship, it could carry 800 lbs of grain. However, the Maengseon became useless and failed to fulfill its role as a warship.

Byeolseon
The Byeolseon was a warship to suppress the Wokou Piracy. They consist of daebyeolseon, jangbyeolseon, and sobyeolseon, and the average number of sailors on board is around 30. The Chuwabyeolmengseon and Chuwabyeolmengseon are special Byeolseon that chase the Wako, but their functions have not been revealed. However, it is believed that one of them may be a special ship like the turtle ship. Another type of Byeolseon is called the Waebyeolseon, but this is not a captured Wako ship; it is made like a Japanese pirate ship for naval practice.

Panokseon
A multideck warship that carries at least 26 cannons but usually carries more (maybe up to 50) and 50 to 60 rowers and sailors and another 125 marines. By having multiple levels, the rowers at the bottom were relatively safe, and marines at the top would have a height advantage over the enemy, firing down upon them and avoiding boarding the ship. The upper deck had a tower in the ship's middle used for command and observation. The deck of the panokseon was broad and flat, making it ideal for the installation of cannons. Panokseons came in different sizes, the largest vessels estimated to range between 70 ft and 100 ft in length with a second row of cannons to fire a broadside and to repel boarders.

Bangpaeseon
A medium-sized combat ship from the late Joseon period armed with 4-6 cannons that erected shield plates on the hull to protect soldiers from enemy arrows and similar threats. It is also called a defensive ship (방선). It is smaller than a warship (전선) and larger than a military ship (병선). It is a combat ship that has shield plates of appropriate height erected on both sides of the upper deck to protect soldiers from enemy arrows and stones. This indicates that the bangpaeseon was developed alongside the bangeunseon during the Eulmyo Japanese invasions. However, there are no records of the bangpaeseon being used in actual combat during the Imjin War. It reappeared after the Imjin War, starting from the reign of Injo.

Turtle Ship
A pre-industrial assault ship clad in spike protruding hexagonal armored plates on the roof and designed for usually ramming enemy ships while firing at point-blank. Its crew complement usually comprised about 50 to 60 fighting marines and 70 rowers. The turtle ship carries 11 cannons on each side. There were two more cannon portholes on the front and back of the turtle ship. On the ship's top at the bow was a dragon's head used as an early form of psychological warfare. It's used as a projector that could generate and release sulfur to obscure vision and interfere with the enemy ships to maneuver and coordinate properly. It was also used as a third cannon port that could fit a cannon in the mouth of the dragon to be fired at enemy ships. The heavy cannons enabled the turtle ships to unleash a mass volley.

Other Ships

 * (범선) are sailing boats for fishing.
 * (비거도선) A barge-like ship that's small and fast to transport supplies to large ships and capture the retreating Japanese. It almost completely disappeared after the Imjin War.
 * (병선) A small warship that escorts large and medium-sized warships and serves as an auxiliary ship transporting supplies and marines.
 * (검선) evolved from the Goryeo-era . There were iron spikes on the roof like the turtle ship, but the  was smaller and usually had a complement of about 15 people.
 * (협선) an auxiliary boat attached to a large warship. Its role was primarily reconnaissance in the early days of the Imjin War. Then it shifted to communication with land, transporting materials to a ship under construction, and civilians.
 * (누선) a large warship with a pavilion.
 * (사후선) a scout ship that sailed ahead of the fleet to observe the enemy's movements, and when they found an enemy ship, it notifies the fleet.

Naval Infantry
The Joseon Navy had several naval infantry units responsible for boarding and capturing enemy vessels and defending their ships during naval battles. These units were known as haejang or haejangdae in Korean, which means "sea soldiers" or "naval troops." The haejang units typically consisted of strong, skilled soldiers trained in land and sea combat. They were equipped with various types of weaponry, including swords, spears, bows and arrows, and firearms. One of the most well-known haejang units was the Geobukseon Haejang, composed of soldiers who served on the famous "turtle ships" (Geobukseon) of the Joseon Navy. These ships were so named because of their unique covered decks, designed to resemble a turtle's shell and protect the crew from enemy fire. The Geobukseon Haejang were highly skilled in close-quarters combat and were known for their bravery and tenacity in battle. Other haejang units of the Joseon Navy included the Jangsa Haejang, composed of soldiers who served on the navy's larger warships, and the Changdae Haejang, a general term for the naval infantry units that served on smaller boats and ships. The Sujebi Haejang was a maritime infantry unit responsible for boarding and capturing enemy ships. They were known for their agility and ability to move quickly on the decks of enemy vessels. The Sujebi Haejang were highly trained in close-quarters combat and were equipped with swords, spears, and other weapons. The Hwacha Haejang was a particular naval artillery unit that operated the Hwacha, a rocket launcher that the Joseon Navy used. The Hwacha could fire multiple rockets simultaneously and was a highly effective weapon against enemy ships. The Hwacha Haejang were highly trained in using this weapon and were considered one of the most fundamental units of the Joseon Navy.

Elite Units
The Joseon Navy had several elite units that were highly skilled and trained for specific purposes. The Haebyeong was a special naval force of the Joseon Dynasty that was responsible for defending the coastlines and harbors of Korea. They were known for their expertise in coastal defense and were equipped with various types of weaponry, including cannons, muskets, and swords. The Haebyeong were highly respected and were considered one of the most important military units of the Joseon Navy.

Sujangdae, also known as Sujeongdae, was a type of naval artillery unit in the Joseon Dynasty. The name "Sujangdae" literally means "water arrow unit" in Korean, and the unit was responsible for operating a type of naval cannon known as the Sujanggun. The Sujanggun was a multi-barreled cannon that could fire multiple projectiles simultaneously. It was typically used for naval battles and coastal defense and was known for its accuracy and effectiveness in combat. The Sujangdae were highly skilled in using this weapon and were responsible for loading, aiming, and firing the cannon during battles. In addition to the Sujanggun, the Sujangdae were also trained to use other types of naval artillery, including rockets and cannons. They were considered a highly specialized and elite unit of the Joseon Navy and played an essential role in defending Korea's coastlines and harbors.

Suyeongsa, was a special unit within the Joseon Navy during the Joseon Dynasty of Korea. The term "suyeongsa" literally means "water ghost division," and the unit was composed of highly skilled naval commandos who were trained in underwater combat and reconnaissance. They were tasked with conducting covert operations, such as sabotage, espionage, and infiltration, against enemy forces. The Suyeongsa were highly respected for their bravery and skill, and they played a critical role in many naval battles during the Joseon Dynasty. They were known for their ability to swim long distances underwater, and for their use of specialized weapons and equipment, such as harpoons, knives, and underwater breathing devices made from animal bladders. The Suyeongsa were also known for their strict code of honor and discipline. They were required to undergo rigorous training and were expected to demonstrate unwavering loyalty to their commanders and fellow soldiers. In recognition of their service, Suyeongsa members were granted special privileges, such as exemption from taxes and military service, and were accorded a high status in society. One of the main roles of the Suyeongsa was to conduct underwater reconnaissance and intelligence-gathering missions. They would swim undetected to enemy ships and harbors, and gather information on the enemy's movements and defenses. They would also plant explosives on enemy ships and infrastructure to disrupt their operations. Another important role of the Suyeongsa was to engage in underwater combat. They would use their specialized weapons and equipment to attack enemy ships and troops, and to sabotage enemy infrastructure. The Suyeongsa were particularly effective in disrupting enemy naval operations, as they were able to attack from unexpected angles and catch their opponents off-guard.

Uniforms
Sailors and military officials wear military uniforms (kunbok, ). The oarsmen, gunners, archers, marines wore black military robes (hyeopsu ) with white trimes. But the gunners, archers, and marines on deck wore light blue long sleeveless vests (jeonbok, ). Red vests representing master-at-arms and yellow vests for military bands. Commissioned officers (usually military yangban) wore a red and yellow military officials coat (dongdari, ) for middle to high-ranking officers and red and blue dongdari for junior-ranking officers with a black jeonbok and a military belt (jeondae, ). During emergencies and wartime, officers, the naval officers and marines wore war clothing (yungbok, ) with a (cheolrik, ) distinguishing rank by color. Red yungbok with a blue military belt represents high-ranking officers. Blue yungbok with a red military belt represents mid-ranking officers. Black yungbok with a black military belt represents junior ranking officers and elite soldiers and cavalry. High and middle-ranking officers wore hats called jeonrip. Sailors and officers of low-rank wore hats called beonggeoji or jukeon.

Armor
The sailors wore no armor or helmets. However, the Joseon military policy required sailors and marines to provide their armor. Padded armor (eomshimgap, ), and padded helmet (eomshimju, ), made from cotton layers, iron plates, and (or) leather was popular among archers and gunners as they offered body protection at lower prices. Sets of leather armor worn by sailors are called Pigabju. Senior naval officers and marines wore a traditional form of Korean armor that persisted with the Mongols' influences during the 13~14th centuries, lamellar armor (jalgap, ). It was a complete metallic armor set. It was composed of a helmet resembling European kettle hats with attached neck defenses of mail or lamellar, body armor reaching down to the thighs or knees, and a set of shoulder guards that protected the upper arm.

In the late dynasty, the dujeonggap is the Korean equivalent of brigandine. The high-ranking officers wore brass scales, and middle-low-ranking officers wore iron. The marines all wore brigandine made from cotton layers, and the plates weaved into the brigandine were either iron, copper, or leather. It became the primary form of Korean armor and often reached below the knees when worn. The helmet assumes a conical shape and has three brigandine flaps that protect the sides and back of the head.

Melee Weapons
The standard Korean sword was the hwando, a short and light curved sword commonly used by Joseon marines during peacetime. The standard Korean spear was the dangpa, a 7–8 ft three-pronged trident with a spear tip in the middle used for close defensive combat to trap an enemy's sword between two of the three prongs. Another polearm used in the navy was the jangchang, a four-meter spear wielded for thrusting and drawing while moving forward and backward. But due to its long length, they cannot use this spear for throwing. The woldo was a 9 ft curved-bladed polearm with a spike at the end of the handle and a tassel or feather attached to the blade. They also carry a pengbae, a round shield, or a deungpaea , a rattan shield along with a sword.

Archery
Joseon sailors and officers often fought as archers with their bows, which had a range of 450 m. Archers also used the pyeonjeon, a short arrow, and the tongah to help guide it as part of the standard kit of Chosun era archers. They can fire at an extended range of 350 meters and flatter trajectories with a faster velocity and penetrating power than regular arrows. Their quivers held 20 arrows and 10 pyeonjeon arrows. They also used repeating crossbows and crossbows.

Gunpowder
In 1395, several weapons were in use: a series of cannons called the daejanggunpo, ijanggunpo, and samjanggunpo, a shell-firing mortar called the jillyeopo, series of yuhwa, juhwa, and chokcheonhwa rockets, which were the forerunners of the singijeon, and a signal gun called the shinpo. These cannons improved during Taejong's rule. Among the people responsible for the developments was Ch'oe Hae-san, son of Ch'oe Mu-sŏn.

The Koreans use the hwacha – multiple rocket-propelled arrows. The hwacha consisted of a two-wheeled cart carrying a board filled with holes into which the singijeon were inserted. It could fire up to 200 singijeon, a type of rocket arrow, all at once. The hwacha also has a variant called the munjong hwacha; it can fire 100 rocket arrows or 200 small Chongtong bullets at one time with changeable modules. The navy used them on panokseons under Admiral Yi Sun-sin to attack Japanese ships from a distance.

The cheon "heaven" or "sky," Ji "earth," Hyeon "black," and Hwang "yellow" or "gold" names are not significant, being the first four characters of the Thousand Character Classic. His son, Sejong, also made many improvements and increased the ranges of these cannons (called hwapo and later hwatong "fire tube" and chongtong "gun tube").

In 1432, the Joseon dynasty under the reign of Sejong the Great introduced world's first handgun, named the seungja chongtong (총통) or "victory gun," which serves as a standard Korean gun. It fires bullets, 15 small pellets, and an iron-tipped arrow. The gunners used the seungja chongtong as a two-handed club in melee combat. Other variants were the soseungja chongtong, a handheld cannon attached to a gunstock that fired a bullet and a large arrow; like the seungja, it could only fire by lighting the fuse. The se-chongtong, was a miniature gun held by its cheolheumja (철흠자, iron tong-handle), which allows a quick change of barrel for the next shot, and fires chase-jeon (차세전, a contemporary type of standardized arrow) with a maximum fatal range of 200 footsteps (≈250 meters). The barrel has a total length of 13.8 cm, inner diameter of 0.9 cm, and outer diameter of 1.4 cm. Initially, Joseon considered the gun a failure due to its short effective range, but the chongtong quickly saw use after fielding to the frontier provinces starting in June 1437. The se-chongtong was used by both soldiers of different units and by civilians, including women and children, as a personal defense weapon. The gun was notably used by chetamja (체탐자, special reconnaissance), whose mission was to infiltrate enemy territory, and by carabiniers carrying multiple guns, who benefited from its compact size.

Another variant was the soseungja chongtong, a handheld cannon attached to a gunstock that fired a bullet and a large arrow, but like the seungja it can only fire by lighting the fuse. In 1596, the seungja were phased out in favor of Japanese-style muskets and arquebuses. The Koreans called these jochong (조총/鳥銃). In the early 1500s, the bullanggi (불랑기/佛狼機), a breech-loading swivel gun, was introduced to Korea from Portugal via China. It was divided into sizes 1 through 5, in decreasing size. The small but powerful cannons of this era saw extensive use during the Japanese invasions of Korea (1592–98) by both the Joseon Navy and the army. Mortars used at this time were the chongtong-wan'gue, byeoldae-wan'gu, dae-wan'gu, jung-wan'gu, and so-wan'gu. These fired stones or the bigeukjincheonre a timed explosive shell. They were very effective against the weaker-built Japanese ships. The Nanjung ilgi says that many captured and used by the Japanese realized their full potential. The Hong'ipo was a cannon introduced from the Netherlands by Hendrick Hamel and others in the 1650s. Joseon also used this cannon during the 1866 French campaign against Korea, the 1871 United States expedition to Korea and the Ganghwa Island incident of September 20, 1875.

Strategy and Tactics
During the Imjin War, Admiral Yi Sun-sin disrupts Japanese supply lines and engage their fleets at strategic locations of his choosing such as straits with small islands and used currents to cripple them. He utilized range and artillery to keep the Japanese from boarding their ships and engaging in Hand-to-hand combat. Throughout his campaign, he used ambush tactics to demoralize them. He used three naval battle formations, "crane-wing formation" (Hakik-jin,, "long snake" formation (Jangsajin, , and the "line abreast formation" (Hoengyeoljin, . To support his formations, he used broadsides and plunging fire to sink the enemy ships.

Yi Sun-Shin's objective was to sink the enemy ships through plunging fire through heavy artillery fire and fire arrows. At the Battle of Okpo, Yi sun-shin fired a broadside to prevent the Japanese from escaping the village. He recorded that "30 enemy ships burnt down to cover the sky with smoke", and in the Battle of Noryang, a record stated, "approximately 200 enemy ships burned with many killed and captured." He used this tactic for seven years on record.

Yi Sun-shin's ambush tactic was to strike the Japanese leader to demoralize their fleet preemptively. In the Battle of Dangpo, he ordered the turtle ship to penetrate the enemy fleet by spearheading the attack on the enemy flagship while decimating the surrounding fleet. Japanese admiral Kurujima Michiyuki was struck by the ship's arrow and fell into the sea. In the Battle of Busan and Myeongnyang, the Joseon fleet focused their firepower on the enemy's flagships and destroyed them. They also hanged their commander's head for his fleet to see like the Daimyo Kurushima Michifusa's at the top of the mast. A Japanese fleet followed their admiral, but without its admiral was a specific target for the Joseon fleet to destroy their enemies when they were confused.

Partisan tactics (Dangpa, were shock tactics to break the enemy. In the Battle of Sacheon, the turtle ship penetrates the enemy fleet while the panokseon supports them with suppressive fire to whither them down. Yi Soon-shin recorded at Dangpo, "The turtle ship came close to the enemy flagship, raised its dragon head, and fired the Hyeonja cannon. Let's hit the enemy ships and break them." Distance and range also became a partisan tactic at the Battle of Busan. Their goal was to destroy the enemy ships rather than kill them, resulting in the sinking of more than 100 enemy ships. Yi Soon-shin utilized this strategy based on the accurate perception of the capability of both sides to gain their victories.

The long-snake formation consists of many ships in a battle line. There were two types of long-snake formations. A long-snake assault formation, where after the turtle ship deploys a Dangpa strategy, a line of panokseons follows behind it at Sacheon. In 1592, Yi Sun-sin assembled the Joseon fleet in Busan and ordered the fleet in a long-snake formation to sink and damage the Japanese fleet docked there while sailing in a circle for a continuous volley.

The crane-wing formation comprises large warships in the center and the reserve with flagship and lighter ships and turtle ships on their wings to surround the enemy fleet. During the Battle of Hansando, Yi Sun-Shin dispatched a small detachment forward to lure the Japanese fleet, and they took the bait, following them into open waters off Hansan Island. He ordered his fleet to surround the Japanese fleet with the cran-wing formation and bombarded the Japanese for the whole day.

The piercing formation (chumjajin, ) is a formation based on a Hanja character that means "sharp." It transitions into a crane-wing formation in two lines where it fires in a continuous volley through rank-fire. A line of ships rotates and fires, and then the following line moves up and does the same.