杨玄感
In 613, with Emperor Yang at the frontlines attacking Goguryeo, Yang Xuangan, who had been apprehensive since he heard rumors that Emperor Yang had remarked, "If Yang Su did not die, his clan would have eventually been exterminated," considered rebelling. Emperor Yang had put him in charge of keeping the supply lines clear near the eastern capital Luoyang, and Yang Xuangan took the opportunity to seize the gathered food supply and then declare a general rebellion against Emperor Yang. At the same time, he secretly sent his servants to Chang'an to summon Li and his brother Yang Xuanting (). Once Li arrived, Yang Xuangan made Li his chief strategist, and Li gave him three options, in the order of Li's opinion as to their feasibility: