In winter 620, with Li Shimin having launched a major offensive against Wang's Zheng state, the Zheng general Yang Qing (, a Sui imperial prince) surrendered Guan Prefecture (, in modern Zhengzhou, Henan), and Li Shimin sent Li Shiji to take over Guan Prefecture. When Wang Shichong's son and crown prince, Wang Xuanying (), heard of this, he headed to Guan from Hulao, but Li Shiji repelled him, and then had Guo write a letter to Wei Lu (), Zheng's prefect of Ying Prefecture (, also in modern Zhengzhou), to persuade Wei to surrender. Wei did so, and this eventually led to a chain reaction where Zheng's holdings in modern eastern Henan surrendered one by one. Wang Xuanying, in fear, fled back to the Zheng capital Luoyang. Further, in spring 621, Wang Shichong's officer Shen Yue () surrendered to Li Shiji, allowing Li Shiji's subordinate general Wang Junkuo () to capture Hulao and capture Wang Shichong's nephew, Wang Xingben () the Prince of Jing.