Founding of the Jin

Also called: Jurchen Jin, Great Jin, Meng’an mouke

Aguda of the Wanyan Jurchens rose against the Liao and founded the Jin in 1115. With an army organised in meng’an–mouke units and an alliance with the Song, he destroyed the Liao by 1125.

The Jurchens of Manchuria had long been under Khitan (Liao) rule and also traded with Goryeo, which they treated as a “parent country”. When the Wanyan clan began uniting the Jurchens in the early 12th century, Goryeo sent Yun Gwan’s Byeolmuban against them in 1107 and built nine forts in the northeast, only to return them in 1109.

Aguda of the Wanyan rebelled against Liao in 1114, won great victories at Chuhedian and elsewhere, and in 1115 proclaimed himself emperor of the Great Jin. The meng’an–mouke system, which grouped 300 households into a mouke and ten mouke into a meng’an, each with civil and military duties, underpinned Jin’s military power; a Jurchen script followed in 1119. In 1120 Jin agreed with the Song in the Alliance Conducted at Sea to attack Liao together, and in 1125 captured the Liao Tianzuo Emperor, ending the Liao. The Liao prince Yelü Dashi went west to found the Western Liao (Qara Khitai) in Central Asia.

When Jin demanded that Goryeo become its vassal, Yi Ja-gyeom overrode opposition and accepted in 1126. In reaction, Myocheong and others called for Goryeo to proclaim its own emperor and attack the Jin.