The rebellion of Jeong Yeo-rip in 1589, known in Korean as the Gichuk oksa (기축옥사, 己丑獄事), was one of the bloodiest political purges in Korea's Joseon Dynasty. Its scale was greater than all four of the notorious literati purges combined. At that time Joseon politics was dominated by conflict between Eastern and Western factions. Neo-Confucian scholar and Easterner Jeong Yeo-rip was accused of high treason, after which as many as 1,000 Easterners were killed or exiled. (Oksa means a major case involving high treason in Korean, and there were several events named oksa during the Joseon period.)