Yuwen Huaji was a Chinese military general, monarch, and politician of the Sui Dynasty who, in 618, led a coup against and murdered Emperor Yang of Sui. He subsequently declared Emperor Yang's nephew Yang Hao emperor and led Emperor Yang's elite Xiaoguo Army (驍果) north. However, he was then repeatedly defeated by Li Mi, Li Shentong (李神通), and finally Dou Jiande. Believing that his defeat was near and wanting to become emperor before his ultimate defeat, he poisoned Yang Hao and declared himself the emperor of a Xu state. Dou captured him in 619 and killed him.

The Sui dynasty was a short-lived Chinese imperial dynasty that ruled from 581 to 618. The re-unification of China proper under the Sui brought the Northern and Southern dynasties era to a close, ending a prolonged period of political division since the War of the Eight Princes. The Sui endeavoured to rebuild the country, re-establishing and reforming many imperial institutions; in so doing, the Sui laid much of the foundation for the subsequent Tang dynasty, who after toppling the Sui would ultimately preside over a new golden age in Chinese history.