Maternal relative of King Seonjong who plotted to enthrone Prince Hansan and was killed by Sukjong's side in 1095
| Life | 미상 ~ 1095 |
| Era | 고려 중기 |
| Clan | 인천 이씨 |
Yi Ja-ui (李資義, d. 1095) was a mid-Goryeo civil official and royal in-law from Incheon, grandson of Chancellor Yi Ja-yeon and son of Chancellor Yi Jeong. His uncle Yi Seok was the father of Queen Sasuk, his sister the Lady Wonsin was a consort of Seonjong, and Yi Ja-gyeom and Yi Ja-ryang were cousins. With such overlapping royal ties he rose under Seonjong.
In 1090 he was sent to Song as Minister of Revenue to express thanks and returned the next year; in 1094, the year of Heonjong's accession, he became Deputy Director and in 1095 Director of the Privy Council, reportedly gathering strength with the support of his cousin Yi Ja-gyeom. Seonjong had made his uncle's daughter queen, and she bore Heonjong, while Yi's sister the Lady Wonsin bore Prince Hansan, Wang Yun. Heonjong was frail, so his mother Queen Sasuk acted as regent.
Since the queen consort Lady So had no son, Yi Ja-ui saw an opening and recruited men to enthrone his nephew Wang Yun. Duke Gyerim, later Sukjong, learned of it and informed Chancellor So Tae-bo and had General Wang Guk-mo mount a show of force; while trying to put it down, Yi was assassinated by Wang's follower Go Ui-hwa. The incident was decisive for Sukjong's rise and shows how members of the same in-law house could meet opposite fates depending on which prince they backed. His fall briefly endangered the line of Yi Ja-gyeom, which later recovered.
Grandson of Yi Ja-yeon and son of Yi Jeong; his sister was the Lady Wonsin, a consort of Seonjong.
While Heonjong was frail he tried to enthrone his nephew Prince Hansan, but was discovered first by Duke Gyerim's side and assassinated.
His tomb was not confirmed.