(1) The Founding of Koryo and National Reunification
At the end of the 9th century, during the reign of Queen Chinsong, Shilla fell into a state of confusion with a weakening of royal authority. Rebellions sprung up everywhere and clan chiefs dominated the local areas. In the territory of Paekche, Kyonhwon established Later Paekche and in the territory of Koguryo, Kung'ye established Later Koguryo. In this way, Shilla was split into three territories which became known as the Later Three Kingdoms. Kung'ye, the King of Later Koguryo which was the greatest among the Later Three Kingdoms, was driven out by his subjects and then Wang Kon took the crown to found Koryo (918). Wang Kon, later known as King T'aejo, renamed Later Koguryo as Koryo as an expression of its restoration and moved the capital from Ch'olwon to his hometown of Song'ak (Kaesong). This founding king aggressively won the powerful local chiefs over to his side, and adopted a policy of love for the people to win over the hearts of the people. Thus, the power of Koryo was strengthened. King Kyongsun, the last sovereign of Shilla, followed the popular sentiments of the people and ceded his sovereignty to Koryo in 935. Thus Shilla fell. In the following year, Koryo attacked Later Paekche, which had been weakened as a result of disputes, and destroyed it in 936. With this, the Later Three Kingdoms, which were in a state of confusion for over 40 years, were reunified by Koryo. Even before this, around the time of its downfall the majority of the Parhae ruling class surrendered to Koryo. Koryo received them and achieved national reunification. In order to restore the old territiory of Koguryo, King T'aejo employed a policy to expand to the north. P'yong'yang was referred to as Sogyong (Western capital) in order to build it into an operational base to develop the north. In the last years of the reign of King T'aejo, the national territory expanded up to the Ch'ongch'on River and Yonghung.

(2) The Establishment of the Ruling Structure
In the early stage of Koryo, local chiefs held a great deal of power, and as a result of the King's political decision to enter into a marriage of convenience, members of the Queen's family entered the palace. The king's authority lacked stability. Thus, Koryo needed to firmly establish a central authority for political and social stability. In order to establish his own authority, King Kwangjong suppressed the powers of the chiefs as well as the Queen's family. He enforced a law governing slaves and set free the slaves who were unlawfully owned by the chiefs. He enforced a Kwago, civil service examination system and employed officials based on the results of these examinations. As a result, the powers of the chiefs were weakened and royal powers were strengthened. Under the reign of King Songjong, more refined institutions were adopted to maintain a system of centralized ruling power. He adopted the ideas of Ch'oe Sung-no, a Confucian scholar-statesman, to make Confucianism the political ideology and reformed the central government organizations and local administrative organizations. Such measures were almost completed during the reign of King Munjong. As the central political organization, King Songjong set up the organizations of Naesa munhasong (later changed to Chungso munhasong), Sangsosong and Chungch'uwon (central council). The Chungso munhasong determined state policies. The Sangsosong was the executive branch and was composed of six departments-Personnel, Military, Treasury, Justice, Rites and Construction-which covered all the official administrative matters. The Chungch'uwon was in charge of receiving and promulgating the King's orders and military secrets. In addition, accounts were kept by the Osadae (office of the inspector) and Samsa, which was in charge of receiving, delivering, and keeping the accounts of money and grains. In the Tobyongmasa (General Military Command), composed of high officials from the Chungso munhasong and Chungch'uwon, they decided on the important policies of the state. The Tobyongmasa was changed to Topyonguisasa in the latter period of Koryo and developed as the supreme organization of the state. During early stage of Koryo, local administration was left to the autonomy of the chieftains, but under King Songjong, 12 divisions to which governors were dispatched were established. Later, local administrative organizations were gradually readjusted and divided the whole country into five provinces and two special provinces. In the two special provinces, military commanders were dispatched and in the five provinces, provincial governors were stationed to govern the cities, counties and Hyon. Hyang, So and Pugok were created, which were special administrative districts where the menials lived. As military organizations, "Two Armies" and "Six Guards" were established as central structures and local armies were also set up. The Two Armies served as the King's royal guards, and the Six Guards were charged with policing the central city (Kaesong) and responsible for national defense. The Supreme Commander of the Two Armies and Six Guards was the Sangjanggun (High general). A military council (Chungbang) gathered to consult on military affairs. The system of land distribution was overseen by the Chonsikwa which was first organized during the reign of King Kyongjong, and then reformed under King Mokjong on the basis of official status. In Chonsikwa, officials were divided into 18 classes and given farms and forestland according to the ranks of the officials. When the officials died, the land was, in principle, returned to the state. Pieces of land referred to as Kongsin-jon were given to meriting vassals, Kong'um-jon were given to officials above the 5th rank, and Naejang-jon were given to members of the Royal House. These lands could be handed down to one's descendants.

(3) Centered on Family Lineage
During the Koryo dynasty, family lineage was regarded as very important. Men born to well-off families enjoyed many privileges as aristocrats. They occupied high government positions and possessed large acreages of farmland. The male children of officials above the 5th rank became government officials without having to pass the civil service exams. This was referred to as the Umso system and aristocrats from good families could retain a high government office for many continuous years. During the middle period of the Koryo dynasty, powerful families controlled the government. They married into the royal house and became powerful members of the Queen's family. Examples of such aristocratic families were the Yi clan of Inchu, the Kim clan of Kyongju and the Ch'oe clan of Haeju.
The Koryo society consist of 4 classes. The high class consisted of the royal family and high aristocrats, the middle class consisted of lower level bureaucrats and technical bureaucrats, the lower class commoners, and the lowest class consisted of menials and slaves. Thus, the middle classes composed of the lowest group of rulers, commoners, and menials were the governed. Merchants and handicraft workers were members of the commoner class. They were responsible for production and bound to provide taxes, imposts and corvee. Slaves, butchers, actors and residents of Hyang, So and Pugok were considered menials. In Koryo, the government organizations of Uich'ang (righteous warehouse), Sangp'yongch'ang (ordinary warehouse) and Bo (foundations) stabilized the life of farmers. To provide relief to poor peasants, the Uich'ang stored and loaned grains during famines or in the spring. The Sangp'yongch'ang purchased grains when prices were low, and when prices soared, it sold the grains in order to regulate the prices. So, Chewibo was a kind of foundation which existed in order to relieve the poor. In addition, the Tong-taebiwon and So-taebiwon (emergency centers of the East and West) were medical facilities for the poor. Industry was centered on agriculture, but the commerce and handicraft industries developed gradually. With the rise in commercial activities, pieces of iron "Konwon-chungbo", "Samhan-t'ongbo" and "Tongguk-t'ongbo" as well as silver bottles were used as currency. But these currencies were not widely circulated. In the Koryo dynasty, "Yondunghoe" and "P'algwanhoe" were observed to offer sacrifices to the indigenous gods. The people engaged in playing ball, riding swings and wrestling during the "Tano" festival which always fell on the fifth day of the fifth month of the lunar calender.

(4) The Military Regime and Changes in the Ruling Power
Entering the 12th century, the foundations of the family-centered aristocratic society began to shake. A member of the Queen's family, Yi Cha-gyom declared war in 1126, and Myoch'ong began a movement to relocate the King's court to Sogyong (P'yong'yang) in 1135. These incidents were pacified, but the abuses and contradictions within the aristocratic society were not rectified. To compound the situation, the practice of favoring civilians and discriminating against the military within aristocratic society became more acute. The military, who were long discontent over their discrimination, rose up with disgruntled others with Chong Chung-bu as their leader in 1170. They deposed and exiled King Uijong, and killed many civilians in order to set up a military government. The new ruling power of the military continued to engage in in-fighting over who would retain power, and this further aggravated political and social confusion. By the end of the 12th century, Ch'oe Ch'ung-hon retained dictatorial power and settled the confusion to some degree. The military coup d'etat shook the family-centered aristocratic society of Koryo. It brought down the civilian structure of control and the military occupied all of the high and important positions. Corruption and tyranny ran rampant under their rule and caused great suffering among farmers and menials. As a result, the peasants everywhere rose up in rebellion, shaking the very foundation of society. Under the guidance of Mang'i and Mangsoi, peasants and menials rose up and in Myonghak-so, Kongju and in Chonju, government slaves rebelled. In Kyongsang-do peasant rebellions under the leadership of Kim Sa-mi and Hyo Sim broke out, and in Kaegyong, Ch'oe Ch'ung-hon's slave Manchok planned a movement to emancipate slaves.

(5) Struggles Against the Northern Tribes
In the Koryo dynasty, the northern tribes of Qidan, N zhen, Mongols were very strong, but by waging fierce struggles against them Koryo safeguarded the country and its people. Koryo implemented a policy of expanding northward from the beginning of its national foundation. Qidan, which stood in confrontation with Song, felt uneasy with Koryo's pro-Song and northward expansion policies and frequently tried to invade Koryo. Under the reign of King Songjong, Koryo's So Hui had a bout with the invading Qidan commander, and retrieved six towns south of the Yalu River. During the reign of King Hyonjong, the Koryo army under the command of Kang Kam-ch'an nearly destroyed the Qidan army which invaded Koryo in Kwiju for the third time. This is known as the Victory of Kwiju (1019) In the 12th century, the N zhen tribe expanded their power to cover the northeastern frontier territory of Koryo. A special unit led by Yun Kwan conquered and built nine walls around the area because of the repeated appeals by the N zhen tribe when this territory was returned. Afterwards, the N zhen, which had regained much strength, founded the nation of Jin and became a powerful nation dominating northern China. Koryo received pressure from Jin for a time, and to repel this, the monk Myoch'ong proposed relocating the capital to Sogyong and sending an expedition against Jin. Ch'oe Ch'ung-hon's dictatorial regime was succeeded by his descendants for four generations during 60 years while the Ch'oe clan strengthened their military government. The Mongols became a powerful world empire in the Asian continent during the 13th century. By demanding that Koryo pay unreasonable tributes the Mongols oppressed Koryo during the reign of King Kojong. The Mongols launched a full-fledged invasion of Koryo in 1231. Military dictator Ch'oe U moved the King's court to Kanghwa Island and prepared to engage in battle. The Mongols invaded Koryo many times for 40 years, but Koryo resisted with the solidarity of the whole nation. The valiant struggles of the peasants and menials were particularly worth noting. But a coup took place in Kanghwa. Ch'oe's military regime crumbled and an approchement appeared between Koryo and the Mongols. Finally, peace was negotiated and the King's court returned to Kaegyong. However, the military unit, the Sambyolch'o, under the command of Pae Chung-son opposed the return of the capital to Kaegyong and continued the war against the Mongols. They moved their base of operations to Chindo and Chejudo, where they continued the resistance struggle for four years. They were finally suppressed by the allied forces of Koryo and the Mongols in 1273.

(6) Safeguarding Independence
After the end of the resistance of Sambyolch'o, Koryo was invaded and pressured by the Yuan (the Mongols named their dynasty Yuan) and Koryo independence was challenged. As a result of pressure by Yuan, Koryo was forced to provide ships and military forces to two expeditions to Japan by the Yuan. Yuan established the Ssangsongch'ong branch of government to govern the land north of Ch'ollyong. With the intervention of Yuan, the official organizations of Koryo were restructured. But even under the intervention of Yuan, Koryo maintained national sovereignty and made efforts to drive out the forces of Yuan. In the mid-14th century, when Yuan was driven back northward by the newly rising kingdom of Ming, King Kongmin adopted an anti-Yuan policy of self rule and enforced reform in politics. King Kongmin attacked the government branch, Ssangsong, and recovered the land north of Ch'ollyong. He restored the official organizations of the nation, expelled pro-Yuan officials and prohibited the practice of Yuan customs. At the time, powerful aristocrats occupied large tracts of land and owned many slaves. The King returned these unlawfully occupied lands to their rightful owners and liberated the slaves. Due to opposition by powerful aristocrats, the King's reform measures failed. Japanese pirates and the Chinese Red Turbans invaded frequently, bringing heavy losses to the Koryo people. In the process of repelling these invasions, military power increased. Ch'oe Yong and Yi Song-gye became famous generals. At the end of the 14th century, an expedition to conquer Liaodong was discussed among the circles of Ch'oe Yong, but on his march north, Yi Song-gye, who led this expedition, went as far as Wihwa Island on the Yalu only to do an about-face. In Kaegyong, he took power and made preparations to establish a new dynasty with a group of new scholars.

(1) Expanding the Cultural Sphere
In the Koryo dynasty, local chieftains came up to Kaegyong to become a part of the aristocracy as government officials, the aristocracy being the leaders of culture. Therefore, in comparison with the Kolp'um system of Shilla, the cultural leaders in Koryo expanded with increased diversity. The cultural sphere during the Koryo dynasty was wider than during the Shilla period. While the system of civil service examinations was enforced and Confucian political ideology was formally recognized, Confucian culture was developed together with Buddhist culture in mutual harmony. Islamic science and technology were introduced via Yuan to further widen the scope of culture.

(2) Development in Confucianism and History
Through the civil service exam system, which was enforced from the time of King Kwangjong, officials were appointed based on their competence in their scholarly knowledge of Confucianism and Chinese literature. Thus, they contributed to the development of these fields. In addition, the encouragement of studies in Confucianism and the establishment of learning institutions of the central "Kukchagam" and local "Hyanghaks" by King Songjong laid the foundation for further development of Confucianism. The "Kukchagam" was the national university for the education of Confucianism. Representative of Confucian scholars during the early years of Koryo was Ch'oe Ch'ung, who was referred to as the "Confucius of the East". Ch'oe Ch'ung established nine private Confucian schools and trained many students. When the government institute of Kukchagam deteriorated, 12 private institutions including the above nine schools boomed. In order to promote government education, King Yejong set up a foundation called the "Yanghyon'go" (Foundation for Training of Talents) and stationed seven specialized lecturers in Kukchagam who faithfully carried out the education. In the latter years of Koryo, the philosophy of "Songri" was introduced to influence society. Different from traditional Confucianism, Songri philosophy was a Neo-Confucianism which sought to answer the fundamental problems of the universe and the humanities. It was introduced to Koryo through Yuan. A Hyang first introduced this philosophy and Yi Che-hyon studied it while associating with Yuan scholars in Yenching, the capital of Yuan. In the latter period of Koryo, Yi Saek, Chong Mong-chu, Kil Chae, Chong To-chon and other scholars made their appearances. During this time, the corruption within Buddhism became notorious and abuses were widely committed by powerful aristocrats. The group of new scholars who made their advent into government studied metaphysics and were critical of the contradictions within Buddhism and confronted the powerful corrupt aristocrats. In the Koryo dynasty, many books were compiled. The most famous is the Samguk sagi (The Historical Records of the Three Kingdoms) written by Kim Pu-sik and the Samguk yusa (The History of the Three Kingdoms) by Iryon, a priest. The Samguk sagi, which is the oldest existing book, recorded the history of the Three Kingdoms from a Confucian perspective. Samguk yusa is a book of narrative literature relating important data regarding the ancient culture from a Buddhist perspective. These books are twin gems and have become the basic material in the study of ancient history. In addition, the Chewangun'gi (Histories of Korea and China) by Yi Sung-hyu, which was written in the form of Chinese poems, and a portion of Haedong kosung-jon (Biographies of High Monks) by Kakhun still exist.

(3) The Flourishing of Buddhism and Typesetting the Taejanggyong
Buddhism in Koryo developed greatly under the protection of the state and the support of the aristocracy. As a result, many temples were erected, the titles of Wangsa (Royal Priest) and Kuksa (National Priest) were conferred on famous monks, and an exam to enter monasteries was included in the civil service examinations. Among the priests of the early Koryo dynasty, Taegak kuksa Uich'on is the most famous. To end the confrontation between the Kyo sect and the Zen sect, he founded the Ch'ont'ae-jong sect. With Buddhism flourishing, typesetting the Taejanggyong created a comprehensive compilation of Buddhist thought. The first prints of the Taejanggyong, begun from the time of King Hyonjong and completed under the reign of King Munjong, were burnt during the Mongol invasion and its woodblocks were lost. Furthermore, Uichon's Sok-changgyong does not exist today, but the Koryo Taejanggyong which was produced in Kanghwa Island during the time of the Mongol invasion is famous worldwide for its accuracy, the beauty of its type styles, and its exquisite woodblocks. These print blocks of Koryo's Taejanggyong consisted of over 80,000 plates, and are often referred to as "P'alman taejanggyong" (Tripitaka Koreana). During the period of military reign, the monk, Chinul, played an important role. The Buddhist sect he established, Chogye-jong, combined many sects of Zen Buddhism. Chinul's Chogye-jong is an attempt to fuse the Zen sect and the Kyo sect from the perspective of Zen Buddhism and has been handed down as the major current within Korean Buddhism. Koryo's Buddhism made great contributions to the development of society and culture, but with its growth, temples began to own large tracts of farmland as well as large numbers of slaves. Monks also engaged in decadent lifestyles or participated in secular activities. For these reasons, during the days of Koryo many people were critical of Buddhism.

(4) Development of Buddhist Art
In the Koryo dynasty, Buddhist art continued to make great strides as it did under Shilla. Stone pagodas, Buddhist images, bells, pictures of Buddha and other Buddhist craftworks were brilliantly created. Among stone pagodas, the 7-story pagoda in the Hyonhwasa Temple, the octagonal nine-story pagoda of the Wolchongsa Temple and the 10-story pagoda in the Kyongch'onsa Temple are the most famous. There are also many beautiful and exquisite works among the tomb pagodas of monks. The Silsang Tower of Hong-pop kuksa in the Chongt'osa Temple and the Hyonmyo Tower of Chigwang kuksa in the Popchonsa Temple well represent the pagodas of Koryo. At present, they are on the grounds of Kyongbokkung Palace in Seoul. The 10-story stone pagoda of the Kyongch'onsa Temple which is representative of the latter period of Koryo has also been moved to Kyongbokkung Palace. As Buddhist images, the sitting image of Sojo Amit'ayorae of the Pusoksa Temple is considered the first masterpiece of Koryo. But on the whole the Koryo Buddhist images are less refined in their artistic workmanship as compared to those of the Unified Shilla. The bells of the Yongju, Ch'onhungsa and T'apsansa Temples are noted as the most beautiful Buddhist bells of Koryo. In the Koryo dynasty, the technologies of inlaying mother of pearl and leaves of silver and bronze into various wares were developed. Among the Buddhist craftworks, there are some brilliant works made by utilizing such skills. Mother of pearl inlaid on lacquered chests which contain figures of Buddhist sutras and gold crested and willow-designed bottles inlaid with pieces of silver are among such works. The wooden architecture of Korea which is still standing began with edifices constructed during the latter years of Koryo. Kungnak Hall within the Pongchongsa Temple in Andong, Muryangsu Hall within the Pusoksa Temple in Yongp'ung and Taeung Hall of the Sudoksa Temple in Yesan are renowned pieces of architecture from the latter period of Koryo. Among them, Muryangsu Hall in the Pusoksa Temple shows beautiful harmony. Buddhist pictures form the majority of paintings from this period. The frescos of Sudoksa and Pusoksa Temples remain and the paintings of Hyeho such as the "Willow Canon" and hundreds of other paintings of Buddhas have been exhibited in Japan. The "Great Hunting in the Heavenly Mountain," said to have been painted by King Kongmin, also remains today. Yi Kwang-p'il and Ko Yu-bang are also known to have been great painters of this age.

(5) Inlaid Celadons of Koryo
Representative of aristocratic art in Koryo is the celadon porcelain, the pride of Korean art. The superiority of Koryo's celadon porcelain lies in its beautiful and clear nephrite color, its balanced form, and its beautiful patterns which are made by a secret inlaying technique. The celadon porcelain of Koryo was developed first as a pure blue porcelain, then the patterns were put in and finally a technique was developed for inlaying celadon porcelain. Inlaid celadon porcelain was peculiar to the Koryo dynasty. It represents the best in the creative abilities and artistic talents of the Koryo people. Celadon porcelain was mostly developed in the 12th century. In the latter period of Koryo, no further progress was made in celadon porcelain techniques, and this art declined. Famous locations for celadon porcelain production were Kangchin in Chollanam-do, Puan in Chollapuk-do, and Kanghwa in Kyonggi-do.

(6) Woodblock Printing, Metal Type, and Science
In the Koryo dynasty, techniques in woodblock printing were further developed and the Taejanggyong was typeset three times. Following that, in the early 13th century, metal type began to be used in printing. This Koryo type was the first metal type in the world, 200 years ahead of the West. In 1234, metal type was used to print a book entitled Sangjong kogum yemun (Ceremonies and Etiquettes of Old and New), but this book does not exist today. Chikchi simgyong (Direct Point of Thinking) published in 1377 is recognized as the world's oldest edition in metal type. In the final days of Koryo, the cultivation of cotton began to change the dress of the people. Mun Ik-chom, who went to Yuan on a diplomatic mission, first brought back some cotton seeds and with his father-in-law, Chong Ch'on-ik, succeeded in cultivating them. Ch'oe Mu-son studied the method of manufacturing gunpowder from Chinese merchants. He made gunpowder weapons and used them to wipe out Japanese pirates. During Koryo's last days, a Hwat'ong togam (smoke stacking plant) was established to make gunpowder weapons run by Ch'oe Mu-son and his technicians. Theories in astronomy and mathematics were imported from Islam to Koryo by way of Yuan. Koryo made further technological developments by expanding cultural exchanges.

(7) Literature and Music
In the earlier periods of Koryo, due to developments in Confucianism and the enforcement of the civil service examination system, Chinese literature advanced. As writers of this period, Ch'oe Ch'ung, Pak Il-lyang and Kim Pu-sik are the most famous, and among poets, Chong Chi-sang was unsurpassed. "On the hill after the rain, the grass looks green," thus began his song of parting which was widely sung as a favorite Iyric. The Hyangga of Shilla was popular into the early years of Koryo and the well-known song by Great Priest Kyunyo was handed down. However, in later years, "Sogyong pyolgok", "Ch'ongsan pyolgok" and "Kasiri" and other ballads were sung as popular favorites. Chinese literature was refined further in the latter Koryo period. Yi Il-lo became famous for his refined poems. Yi Kyu-po composed "King Tongmyong" which sung of the traditions of Koguryo and awakened the historical consciousness of the people. Development of literature, narrating and legendary tales flourished. Yi Il-lo's P'ahan-jip, Ch'oe Cha's Pohan-jip and Yi Che-hyon's Yogong paesol were among such works. Yi Kyu-po's Tongguk isangguk-chip is famous as an anthology of poems and prose. With developments in Confucianism and Chinese literature, famous calligraphers appeared. In the Koryo dynasty, among calligraphers, Yu Sin, T'an Yon and Ch'oe U were the most outstanding. Together with Kim Saeng of Shilla they became known as the four writing saints. In later Koryo, Songsolch'e of Chao Meng-pu style which was imported from Yuan was popularized in Koryo. Under the reign of King Ch'ungson, Yi Am became known as a master of writing in this style. Among Koryo music, the traditional Hyang-ak continued and Taesongak, the classical music of China, was imported from Song and developed as the court music called A-ak. As musical notes of Hyang-ak, Tongdong, Taedong-gang, and Hallim pyolgok were used and as musical instruments, Komungo and Kayagum were used. In China, the traditional Taesong-ak has disappeared but in Korea, A-ak is still heard today. Also in Koryo, mask dances such as Ch'oyongmu were in vogue.

(1) Exchanges with Song
Koryo and Song established friendly relations for a long time. Koryo enforced pro-Song policies in order to import advanced culture from Song, and Song wished to join with Koryo in order to confront the threat from the northern tribes, so exchanges were active. Koryo began exchanges with Song under the reign of King Kwangjong, and later, many missions visited Song, dispatching large numbers of students and monks. Merchants also traveled to Song frequently. Kim Haeng-song and Ch'oe Han, students from Koryo, studied in Guozijian and Koryo's monk, Uich'on, studied Buddhist doctrines in Song and brought back many Buddhist books. Before this, in the earlier stages of Koryo, Uit'ong and Ch'egwan sailed to China and engaged in many activities. Uit'ong became founder of the Ch'ontae-jong sect in Song and Ch'egwan arranged the fundamental creed of Ch'ontae-jong in the famous book entitled "The Creed of Ch'ontaesa". Many Chinese subjects were naturalized as citizens of Koryo and engaged in activities in Koryo. Many were apt writers and became government officials in Koryo. Ssang Ki (Shuangji) during the reign of Kwangjong and Zhouzhu under the reign of King Mokjong are examples of such personages. The Song envoy, Xujing, wrote "A Pictorial of Koryo" introducing the things of Koryo to China and praising the celadon porcelains of Koryo as world masterpieces. Trade was active between Koryo and Song; Koryo exported gold, silver, ginseng, mats woven with flower designs and works inlaid with mother of pearl and imported brocades, medicines and books from Song. Song porcelains influenced the development of the celadon porcelain in Koryo, and the Taesong-ak of Song became the court music of Koryo.

(2) Exchanges with Qidan and Nuzhen
From the first stages after its founding, Koryo enforced a policy to march northward in order to recover the territories of old Koguryo. Thus, Koryo often clashed with the kingdom of Qidan which destroyed Parhae and ruled over Manchuria. Thus, exchanges between Koryo and Qidan were not active. Koryo exported grains and stationary and imported silver and fur from Qidan. After the destruction of Parhae, the Mohe tribe lived in scattered groups throughout Manchuria as well as in the northern frontiers of Koryo. Some of them referred to Koryo as their parent country and offered gifts to Koryo as tribute. In the 12th century, Nuzhen became a powerful nation and founded the unified kingdom of Jin, and Koryo was subject to the threats of them. For this reason, trade between Koryo and Nuzhen began, but not actively. Koryo imported silver, fur and horses from Nuzhen and exported farm implements and grains.

(3) Contacts with Islam
The islands of the Saracen Empire in southwest Asia engaged in active trade with China, and the Arabian merchants of the Saracen Empire carried on commerce with Shilla by sailing to Ulsan via China. During the Koryo dynasty, large groups of Arabian merchants arrived at Pyongnan Island to engage in trade. Pyongnan Island prospered as an international trading port at the mouth of the Yesong River where Song and Arabian merchants brought mercury, spices and corals, and Koryo gave them gold and brocades in exchange. Through their visits, Koryo became known to the West and that is how Korea got its Western name.

(4) Exchanges with Yuan
In the 13th century, relations between Koryo and Yuan became closer, and they engaged in active cultural exchanges up to the mid-14th century. Visitors coming and going did not cease for 80 years and customs were exchanged. Among the upper class of Koryo, Mongolian was spoken and Mongolian customs were practiced as the cultures of the two countries were mutually exchanged. Marriages were often contracted between the royal families of the two countries and a Koryo woman from the Ki family became Empress to King Shundi of Yuan. King Ch'ungson of Koryo built Man'gwon-dang (Hall of Ten Thousand Books) in Yenching to facilitate scholarly exchanges between the two. Koryo's Yi Che-hyon and Yuan's Chao Meng-pu made their scholastic debutes in the Man'gwon-dang. Later, many writers of Koryo often visited Yuan and exchanged their customs. At that time, Yuan was a world empire and imported cultures from various countries. As a result, Koryo was able to import Saracen culture through Yuan, and the Saracen developments in science and technology, astronomy, mathematics and medicines were influencial in bringing about similiar developments in Koryo. For example, the astronomical observatory "Soun'gwan" was built, and observation equipment used for the study of astronomy was improved, while the Yuan almanac "Shuigkili" was imported. Metaphysics was introduced from Yuan and the scholars of metaphysics propelled many social and cultural reforms. The skills of gunpowder manufacturing and cotton cultivation were also imported from Yuan. In these ways, the Koryo-Yuan exchanges gave rise to the development of much of the culture in Koryo.

(5) Exchanges with Japan and the Southeastern Islands
Between the 9th and 12th centuries, diplomatic relations with Japan had been severed, but with the weakening of the Japanese legal system, local Japanese military officials began to grow in power and the Daimyo's or local lords' post-military forces expanded their power in the west. Thus traders of western Japan and Tazaifu actively engaged in relations with Koryo. Japanese envoys and merchants brought sulphur and mercury to Koryo while Koryo sent them the Taejanggyong, books and ceramics to be used for tea ceremonies. In the latter period of Koryo, relations with Japan deteriorated. The expedition of Koryo-Yuan allied forces to Japan failed and the repeated invasions and attacks by Japanese pirates meant huge losses for Koryo. Pak Wi, during the reign of King Ch'ang, once attacked Tsushima, one of the island posts of Japanese pirates and overturned the pirate forces in 1389. In the last days of Koryo, the Loochoos and Thailand of southeast Asia sent envoys to Koryo to offer their native products, and Koryo returned the gesture by also sending them gifts. In this way, there were some exchanges with the Loochoos and Thailand.