Speaking of Xu Yan, everyone will think of the idiom "being in Cao Yingxin and Han". Xu Yan was a conspirator of Liu Bei and was seduced by Cao Cao to Xudu. Although others in the Cao Wei Group vowed not to offer a plan for Cao Cao all his life, However, when Xu Xu later left Cao Wei, he recommended Cao Wei to Sima Xu. It was Sima Xu that led to the failure of the Northern Expedition of the Shu Kingdom and helped Cao Wei unify the three kingdoms. It can be said that without Xu Xu's recommendation, the outcome of the Three Kingdoms is not yet known, why did Xu Xu think of Cao Wei What about Sima Yi? Why did Xu Yan change his mind? Chen Sheng thinks so.
Xu Xun is filial and has good intentions. Because of Liu Bei's love, he took the initiative to assist Liu Bei. He helped Liu Bei to break Cao Ren's eight-door golden lock array in Fan City, making Liu Bei Group's fame and defeat. Cao Cao used Xu Yang ’s mother to design Xu Xu to Xu Du. Xu Yang ’s mother was sensible, and after learning that Cao Zei was going to use her son, she immediately hanged herself. Xu Xu saw her mother died, and she hated Cao Cao even more. Still thinking about Liu Bei, he was determined not to offer a plan for Cao Cao all his life.
Although Xu Xun was unwilling to serve Cao Wei, he was very close to Cao Cao's younger son Cao Chong. Cao Chong was intelligent and diligent in studying since he was a little boy. He left an allusion in the history of "Cao Chong's name". Zi Xiancai naturally loved Cao Chong, a clever and eager to learn. After Cao Cao knew it, Xu Xu became Cao Chong's teacher. Unfortunately, Cao Chong died at a young age. Xu Xu lost his lover and was sad. He no longer wanted to stay in this meaningless Cao Wei. So he wanted Cao Cao to ask that he would not contaminate the world again, and wanted to return to the mountains and forests. Residual.
Cao Cao was worried that Xu Xu would go to assist Liu Bei after he left. While pretending to agree with his request, Cao Cao sent his son Cao Xu to hunt Xu Xu overnight. However, Cao Yong is a very talented person. He has always admired Xu Yan's knowledge and is unwilling to kill Xu Yan, so he explained the situation to Xu Yan and let him go. Xu Zheng was very moved. He knew that Cao Yu was vying for the position of Cao Weishizi and needed talents, so he recommended Sima Yi to him. Later, Cao Yu defeated his brother Cao Zhi with the help of Sima Yi, succeeded in winning the position of son, and became the emperor after unifying the three kingdoms.
However, in addition to Cao Yong's love for talent, Xu Zheng recommended that Sima Yi should have a more important reason. He saw that Sima Yi was a talented and ambitious person. Once Sima Yi, the head mound tiger, is released, he will not only help Cao Wei establish a hegemony, but also pose a great threat to Cao Wei. Sure enough, the Cao Wei regime was finally defeated by Sima Yi. This is why Xu Yan recommended Sima Yan.