After the fall of the Tang Dynasty, China entered a chaotic period of five dynasties and ten kingdoms, with various forces vying for power and frequent regime changes.
On the Korean Peninsula, in the 2nd year of King Gyeongmyeong of Silla (918), a palace coup d'état took place in the Taebong-kingdom, and the general Wang Jian established himself as king, established the Goryeo Dynasty, and unified the entire peninsula in the 11th year of King Taejong of Liao (936).
At the same time, the Khitan power in the north grew stronger, and in the fourth year of the reign of Tang Tianyou (907), Liao Taizu established the Khitan state in the valley of today's Inner Mongolia's West Lamulun River.
When the power of the Liao Kingdom grew stronger and expanded in all directions, at the same time, Goryeo also formed a situation in which the three kingdoms of Gobaekje, Taebong, and Silla were established after the state of the Hao clan division since the end of Silla, until the 10th year of the reign of Emperor Taejong of Liao (935), when Goryeo destroyed Silla, and the following year destroyed Gobaekje, ending the fragmentation of the Korean Peninsula.
During this period, the two countries established a deep relationship, and from the very beginning of the establishment of diplomatic relations, there were official exchanges and exchange of gifts.
At the beginning of the establishment of the Liao Dynasty, Goryeo once presented a sword as a dowry gift to Liao Taizu to congratulate him on the founding of the country. Subsequently, Liao also sent envoys to Goryeo and sent gifts such as camels, horses, and felt.
Interactions during this period were only ceremonial rather than substantive. The purpose of establishing a relationship between Liao and Goryeo was to congratulate each other on the founding of the state, to pursue peaceful diplomacy, and to expand their own power.
For the Liao Dynasty, due to the merger of the eight Khitan tribes before the founding of the People's Republic of China and the successive wars of foreign conquest, its territory has expanded rapidly, and its sphere of influence extends to Hequ and Yueyin Mountain in the south, Ganzhou in the west, Orkhon River in the northwest, and most of Liaoxi and Liaodong in the northeast.
However, at that time, there was still the opposing Bohai State in the northeast of Liao, and there were also Turkic, Dangxiang, Tuyuhun and other remnants in the northwest, which became a worry for Liaonan to enter the Central Plains.
In order to better expand, within a few years after the founding of the People's Republic of China, Liao first pacified the remnants of the northwestern tribes, and then began to plan the eastward expedition to the Bohai Sea. In order to seize the Central Plains and annex the Bohai Sea, the Liao lost no time in establishing a relationship with Goryeo after the founding of the state, hoping that when it invaded the Bohai Sea and the Central Plains in the future, Goryeo would maintain a neutral position and ensure that Liao's expansion activities would not be disturbed and contained.
On the Goryeo side, although Taizu Wangjian admired Chinese civilization and rejected Yidi customs, considering the unstable factors in the country and the situation on the peninsula at the beginning of the founding of the country, he still adopted a foreign policy of active reconciliation with Liao, hoping to strive for a favorable external environment for the realization of the great cause of the three kingdoms after reunification in the future.
The Song Dynasty took advantage of the reform achievements of the Later Zhou Dynasty and adopted a strategy of first the south and then the north, and began to strain relations with the Liao and Northern Han. The Song Dynasty tried to annex the Northern Han and then attack the Liao, who wanted to use the Northern Han to contain the Song Dynasty.
At the same time, Goryeo also clashed with Liao over territorial issues. In order to expand its territory, Goryeo repeatedly sent troops to attack the Jurchens and obtained territory on the south bank of the lower reaches of the Yalu River.
Liao was very dissatisfied with Goryeo's expansionist behavior, believing it to be a demonstration against Shangguo. Liao believed that the main contradiction was to compete with the Song for the world, and if the Song could be conquered, Goryeo would surrender without a fight.
Between Liao, Song, and Goryeo, Goryeo skillfully played a balance to protect its own interests.
Originally, Goryeo adopted the diplomatic means of seeing the wind and steering the rudder and meeting the source left and right, but with the strength of the Liao State, Goryeo knew that it was difficult to match, so it called the Liao State a tribute. However, the Liao State focused its main efforts on dealing with the Song State, which gave Goryeo an opportunity to take advantage of the Liao Dynasty to expand its territory in time, even to the banks of the Yalu River.
This angered the Liao rulers, which led to a war between Liao and Goryeo, and relations between the two countries took a sharp turn for the worse. In order to fight against the powerful Liao State, Goryeo repeated its old tricks and tried to form an alliance with the Song State, forming a situation of flanking the Liao State before and after.
The friendly reception of Goryeo by the Song Dynasty allowed exchanges between the two countries to develop. The friendly warmth of the Song Dynasty towards the Goryeo envoys showed the importance of the relationship between the two countries. The Song Dynasty fulfilled Goryeo's requirements in terms of culture and economy, and promoted exchanges between the two countries.
The close contacts between Goryeo and the Song Dynasty stimulated the Liao state, and Goryeo's refusal to claim vassal status on the Liao state continued to encroach on the area east of the Yalu River, forcing the Liao state to resolve to establish a tributary relationship between the two countries by force.
Liao Shengzong launched a war against Goryeo in the east, but had to give up due to the difficulty of the army's march. Eventually, Goryeo paid tribute to the Liao State, and the tributary system of the two countries was formally established.
This was a tributary system established by the Liao State by forcing Goryeo by force. Although the relationship between the two countries was intermittent, the land of the six states east of the Yalu River was still owned by the Liao State.
Goryeo skillfully pursued diplomatic tactics between the two countries. Despite negotiations with Liao on the eastern boundary of the Yalu River, no agreement was reached. After the rise of the Jurchen Wanyan tribe, Goryeo began to engage diplomatically with it, while also maintaining friendly relations with Liao.
Goryeo's diplomatic strategy revolved around maintaining domestic stability and security, as well as balancing with external forces. When the Jurchen Jurchens returned to the Yan tribe, Goryeo sent troops to the Northern Expedition in an attempt to protect their own interests.
However, this move was opposed by the Khitans, and Goryeo was forced to return the nine cities it had built to the Jurchens. At the same time, Goryeo also took into account the attitude and pressure of the Khitan before making this decision.
Finally, with the corruption of the Liao Dynasty and the resistance of the Jurchens, the Liao-Jin War officially broke out. Goryeo played an important role in this, and its diplomatic strategy contributed to maintaining its own interests and security.
Due to repeated defeats, Emperor Liao Tianzuo deployed a transfer to the Tokyo Soldiers and Horses, demanding an in-depth attack on the Jurchen border and taking prisoners away. However, Goryeo did not respond. In the first month of the first year of Jin Harvest (1115), Wanyan Aguta was officially proclaimed emperor, with the founding name of "Dajin" and the year name of "Receiving the Country".
As a result, the relationship between the Jurchen League and Goryeo became the relationship between the Jin Dynasty and Goryeo. Emperor Tianzuo decided to personally recruit and send Goryeo to ask for troops. At that time, the Jin soldiers had captured Huanglongfu, an important town in eastern Liaodong, and the Liao soldiers were invincible.
Emperor Tianzuo sent Goryeo again and asked Goryeo to send troops. However, Goryeo still did not send troops, and even Liao envoy Yeluyi and others "retreated without courtesy". Seeing that Liao was about to die, Goryeo automatically canceled the Zhengshuo era name of Liao.
From then on, Liao Zhengshuo, who had been in Korea for more than 120 years, was abolished, announcing the end of the tributary system between Liao and Goryeo, and the international order in East Asia, centered on the Khitan, was shaken.
In this context, in the sixth year of Liao Tianqing (1116), the gold lord Aguta sent an envoy to Goryeo to ask Goryeo to recover the city of Baozhou. Goryeo also sent an envoy to the Jin Dynasty to ask the Jin lord to return the city of Baozhou.
The golden lord said to the messenger, "Go and fetch yourselves." In March of the following year, the Jin soldiers captured Baozhou, and then attacked the distant city, and the Yuantong army Yeluning ran out of food, so he had to abandon the city and flee to the sea by boat.
Although Goryeo and Liao still sent envoys to each other, it was difficult to realize real tributes and gifts due to road obstacles. After the accession of Goryeo Injong, the communication between Liao and Goryeo was de facto interrupted.
After the fall of the Liao Kingdom, the Goryeo Kingdom tried to communicate with the Liao by sea, but was unsuccessful. After that, the state of Kim made a request for Goryeo to be a vassal, and there were disagreements in Goryeo about this.
After discussions at the meeting of the hundred officials, Goryeo finally sent an envoy to the Jin kingdom in the summer of 1126 to pay tribute to the Jin kingdom and present gifts, establishing a vassal relationship with the Jin kingdom and establishing a tributary system.
From then on, the Jin state became the suzerainty of East Asia and the Korean Peninsula, changing the political order of East Asia, so that the international order of East Asia in the early twelfth century was centered on the Jin dynasty.
Goryeo was incorporated into the ** system order centered on the Jin Dynasty, which further strengthened the system.
This tributary relationship lasted for more than a hundred years until the fall of the Jin Dynasty in the sixth year of the reign of Emperor Taizong of Mongolia (1234).