Xin Pi
Some time later, an official Bi Gui submitted a memorial to Cao Rui as follows: "Wang Si (王思), the Supervisor of the Masters of Writing, is a diligent and accomplished senior official. However, he is not as good as Xin Pi in virtue and strategy. I recommend Xin Pi to replace Wang Si." After reading Bi Gui's memorial, Cao Rui sought Liu Fang and Sun Zi's opinions. They said: "Your Majesty chose Wang Si because you saw that he is a practical and hardworking person who doesn't care how others see him. Xin Pi may have a good and virtuous reputation, but he is too straightforward and domineering. Your Majesty should carefully consider this issue again." Cao Rui eventually did not replace Wang Si with Xin Pi, and instead promoted Xin Pi to serve as Minister of the Guards ().