Yang Xuangan
Sometime between 607 and 613, however, Su was again named the head of the examination bureau. In 613, when Yang Su's son Yang Xuangan rebelled against Emperor Yang in the midst of Emperor Yang's second campaign against Goguryeo, Emperor Yang asked Su whether Yang Xuangan, whom Emperor Yang considered intelligent, was capable of causing great trouble. Su responded, "Only a person who is capable of judging what is right and wrong and what is successful and unsuccessful can be called intelligent. Yang Xuangan is careless and unattentive, and he will not cause much trouble. What I am afraid of is that he is merely starting the prelude of great troubles." Much as Su feared, while Yang Xuangan's rebellion was quickly suppressed, thereafter, there was little peace for the rest of Sui's history.