杜如晦
Li Shimin decided to take action and planned to dispose of his two brothers at the advice of his subordinates, especially Zhangsun Wuji, Fang Xuanling, Du Ruhui, Yuchi Jingde, and Hou Junji. Li Shimin sent Zhangsun to recall his two most important advisors Fang Xuanling and Du Ruhui to help plan the course of action. After being summoned in secrecy, Fang and Du disguised themselves as Taoist priests and traveled to Li Shimin's camp to discuss the strategy. Li Shimin also bribed Chang He (), who at the time was the military commander guarding the Xuanwu Gate, into following his orders. Few years prior, Chang had been an officer under Li Shimin, but he was eventually reassigned to a key position at the Xuanwu Gate in 624.