Yuwen Shu
After the campaign against Chen, Emperor Wen's son Yang Guang the Prince of Jin, who was in overall command of the campaign against Chen, became the commandant at Yang Province (揚州, roughly modern Yangzhou, Jiangsu). Yuwen Shu was friendly with Yang Guang, and Yang Guang, whose ambitions included displacing his older brother Yang Yong the Crown Prince as his father's heir, therefore requested in 600 and received Emperor Wen's approval to have Yuwen's command post moved to Shou Province (壽州, roughly modern Lu'an, Anhui), closer to Yang Guang's post. At one point, Yang Guang consulted Yuwen Shu as to how he could displace his brother. Yuwen suggested entering an alliance with the powerful official Yang Su—and forming the relationship with Yang Su through Yang Su's brother and confidant Yang Yue (楊約). Yang Guang therefore gave Yuwen much treasure and had him go to the capital Chang'an to try to meet Yang Yue. Yuwen offered some of the treasures pillaged from Chen to Yang Yue, and then also intentionally lost to Yang Yue when the gambled. After he had become sufficiently familiar to Yang Yue, he revealed to Yang Yue that it was Yang Guang's intent to enter into an alliance with Yang Su—persuading Yang Yue that given that Yang Su did not have a warm relationship with Yang Yong, his family would be in danger if Yang Yong were to succeed Emperor Wen. Yang Yue, in turn, persuaded Yang Su, who subsequently persuaded Emperor Wen and Emperor Wen's wife Empress Dugu that Yang Yong should be deposed. Emperor Wen and Empress Dugu agreed, and in 600 Emperor Wen deposed Yang Yong and replaced him with Yang Guang. Yang Guang made Yuwen Shu a commander of his palace guards and gave his daughter, the Princess Nanyang, to Yuwen Shu's son Yuwen Shiji (宇文士及) in marriage.