During Emperor Xiaomin's Reign
Yuwen Jue took the throne (as Emperor Xiaomin), but did not use the title "emperor" (皇帝, huáng dì), using instead the Zhou Dynasty-style title "Heavenly Prince" (Tian Wang). He created Yuwen Hu the greater title of Duke of Jin.
The political situation, with Yuwen Hu as regent, was unstable. About a month after Emperor Xiaomin took the throne, two of the most senior officials, Zhao Gui (趙貴) the Duke of Chu and Dugu Xin the Duke of Wei, showed signs of displeasure about Yuwen Hu's hold on power. Zhao wanted to kill Yuwen Hu, an action that Dugu tried to persuade him against. Soon thereafter, however, Zhao's plans were revealed by another official, Yuwen Sheng (宇文盛), and Yuwen Hu had Zhao executed and removed Dugu from his office. Soon, he also forced Dugu to commit suicide. When another official, Qi Gui (齊軌), criticized Yuwen Hu's regency, he was also executed.
Meanwhile, Emperor Xiaomin himself, wanting to take power, was engaging in a plot to kill Yuwen Hu. His plot included two of Yuwen Tai's key associates, Li Zhi (李植) and Sun Heng (孫恆), as well as the other officials Yifu Feng (乙弗鳳) and Heba Ti (賀拔提), each of whom was ambitious and therefore further tried to fan Emperor Xiaomin's suspicions against Yuwen Hu. After Li tried to engage another official, Zhang Guangluo (張光洛) in the plot, however, Zhang revealed the plot to Yuwen Hu. Yuwen Hu, not wanting to take drastic actions at first, sent Li and Sun away to be provincial governors. When Emperor Xiaomin wanted to summon Li and Sun back to the capital Chang'an, Yuwen Hu urged against it, pledging his loyalty. However, Yifu and Heba became fearful and plotted to carry out the plot anyway. Zhang again informed Yuwen Hu, who discussed the matter with the generals Helan Xiang (賀蘭祥) and Weichi Gang (尉遲綱). Helan suggested to him to depose Emperor Xiaomin, and Yuwen Hu had Weichi arrest Yifu and Heba and disband the imperial guards. Emperor Xiaomin, surprised by the move, barricaded himself in the palace and armed his ladies in waiting and eunuchs. Yuwen Hu sent Helan into the palace to force Emperor Xiaomin to leave the palace and put him under house arrest at his old residence as the Duke of Lüeyang.
Yuwen Hu summoned the high level officials and informed them the situation, proposing to depose Emperor Xiaomin and replace him with Emperor Xiaomin's older brother Yuwen Yu the Duke of Ningdu (who was not named heir by Yuwen Tai because his mother Lady Yao was a concubine). The high level officials, not daring to oppose Yuwen Hu, agreed. Emperor Xiaomin's coconspirators were executed, while he himself was demoted to the rank of Duke of Lüeyang. A month later, Yuwen Hu executed him and forced his wife, Princess Yuan, to become a Buddhist nun. Soon thereafter, Yuwen Yu arrived at Chang'an and took the throne (as Emperor Ming), still using the title of Heavenly Prince.
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