 Yang Yichen then engaged another major rebel leader, Gao Shida (高士達), who had claimed the title of Duke of Donghai.Around the new year 617, Gao, going against the advice of his subordinate Dou Jiande, engaged Yang Yichen, and Yang Yichen defeated and killed Gao and nearly captured Dou.However, believing that Dou to not pose a further threat, he did not pursue Dou further.