Yi Ŭi-bang (Korean: 이의방; Hanja: 李義方; 1121 – 12 January 1175) was a military ruler of Korea during the Goryeo period.^[1] He was one of many military dictators of Goryeo in the aftermath of the 1170 warrior rebellion.

Yi originated from the Jeonju Yi clan. He subsequently joined the military and rose in ranks, becoming a minister in the scholar dominated government.

In August 1170 (Uijong 24th year), he joined the Goryeo warrior rebellion, which occurred in defiance against the typically minister ruled Korea. Primary leaders of this rebellion was Chŏng Chung-bu and Yi Ko who found that warrior-class treatment was truly unfair and planned a coup d'état to establish a warrior government.^[2]

The King of Goryeo, Uijong was soon disposed and the new warrior-class ministers set up a puppet king Myeongjong. Yi was named as one of the key figures in the new regime with the title of High Merit Minister (Hanja: 壁上功臣) and given special privileges along with the other ministers. When Yi Ko tried to plot a coup and get hold of a dictatorship in 1171, Yi, under the orders of Chŏng Chung-bu purged and murdered Yi Ko.

With Chong, Yi increased the size and power of the military and attracted military-class administrators to the regime and appointed these men to national offices which were previously reserved for scholar-class ministers. In 1173, when a scholar-class minister Kim Po-dang (김보당; 金甫當) attempted to restore disposed king Uijong to the throne, Yi decisively slew the former king, preventing any further restoration attempts. With this merit, he was further promoted to Commander of Land Troops.

During his co-governance with Chŏng, Yi also faced a series of Buddhist Monk uprisings from different shrines around the nation. As Goryeo was officially a Buddhist nation since Wang Kŏn's unification of Korea, the Buddhists had great influence upon the government and most Goryeo kings appointed official Buddhist Great Monk advisors to assist in national administration. Due to the increasing Buddhist uprisings, Yi himself commanded his forces to put down these rebellions and raid Buddhist shrines. With his powerful forces, he swept the nation and raided and pillaged these shrines.

At this time, Cho Wi-ch'ong (조위총; 趙位寵), a general of the North-Western border attempted to start a rebellion. Yi responded by murdering favorers of this rebellion such as Yun In-mi (윤인미; 尹仁美), who was of Seogyung birth. Due to this action, Yi lost support and favors from the people, and when he attempted to put down this rebellion, he failed.

Yi, attempting to put down Chŏng and gain more power, tried to appoint his daughter as Royal Princess consort, an action which did not fulfill his objective but instead further endangered Yi's political situation. Due to this action, the 2nd Jo Invasion force, led by Chŏng Chung-bu's son Chŏng Kyun subsequently murdered Yi Ŭi-bang and his supporters and removed his daughter from the royal family. However, soon enough, Chŏng Chung-bu was also murdered and the young and righteous dictator Kyŏng Tae-sŭng took power.

General Yi Ŭi-bang's main legacy remains in the balance that was achieved through the purging of scholars during his co-governance with Chong. Before the arrival of Yi, the scholar class had more influence in the government to the extent that the warrior-class was greatly mistreated. With the changing of kings and shifting of power from scholar-class to warrior-class, Goryeo faced a new era. A final and very important legacy is his connection with the founder of the Joseon Dynasty, Yi Sŏng-gye. Yi Ŭi-bang's younger brother Yi In was a 6th generation ancestor of Yi Sŏng-gye, thus connecting Yi Ŭi-bang and Yi Sŏng-gye together.

• Father - Yi Yong-bu, Prince Daejang (대장군 이용부; 李勇夫)
• Mother - Lady Yi (이씨)
• Sibling(s)
  • Older brother - Yi Chun-ŭi (이준의; 李俊儀; ? – 1174)
  • Younger brother - Yi Rin or Yi In (이린/이인, 李璘/李隣)
  • Younger brother - Yi Kŏ, Internal Prince Consort Sayeol (사열부원군 이거; 沙熱府院君 李琚)
• Wife - Lady Cho (조씨; 曺氏)
  • Daughter - Queen Sapyeong of the Jeonju Yi clan (? – 1174/1175)
    • Son-in-law - Gangjong of Goryeo (10 May 1152 – 26 August 1213)
      • Granddaughter - Princess Suryeong (1174/1175 – ?)
        • Grandson-in-law - Wang Ch'un, Duke Hawon (하원공 왕춘)

• Portrayed by Seo In-seok in the 2003–2004 KBS TV series Age of Warriors.

• History of Korea
• List of Goryeo people