During the Three Kingdoms period, Eastern Wu seized a strategic stronghold and killed Shu's great general Guan Yu. Shu's ruler, Liu Bei, blinded by rage over his sworn brother's death, ignored repeated warnings from his chancellor Zhuge Liang and launched a campaign for revenge—only to suffer a crushing defeat.
Liu Bei retreated to Baidicheng (present-day Fengjie, Sichuan) and fell gravely ill. He sent for Zhuge Liang and entrusted him, saying, "Your abilities are ten times greater than Cao Pi's, and you have the talent to stabilize the state. If my son is worthy of guidance, guide him; if he proves unworthy, you may take his place."
With these final words, Liu Bei passed away. After his death, his son Liu Shan ascended the throne, and Zhuge Liang resolved to assist him in restoring the Han dynasty.
Seeing that Shu had suffered a crushing defeat in its campaign against Wu and that their lord had recently passed away, Meng Huo, the Yi chieftain living south of Shu, seized the opportunity to raise an army and attack. Zhuge Liang, recognizing that the kingdom's military strength was severely depleted and that Liu Bei had just died, deemed it unwise to engage in further conflict. Instead, he sent envoys to pacify the southern tribes, restored the alliance with Eastern Wu, and focused on strengthening agriculture and training soldiers at home, laying the groundwork for future campaigns.
A few years later, when the Kingdom of Shu had regained its strength, Zhuge Liang personally led a massive army to subdue Meng Huo. Choosing to win through virtue rather than force, he captured Meng Huo seven times and released him each time. Finally, Meng Huo surrendered in genuine admiration, declaring, "Your grace is unmatched—I submit to Shu Han with all my heart."
After securing the rear, Zhuge Liang decided to campaign against Cao Wei to fulfill Liu Bei's dying wish. Before departing, he submitted a "Memorial on Sending Out the Troops" to Liu Shan, beginning with how the late emperor failed to complete his cause before his death, stating that he had "received the appointment at a time of defeat and accepted the command in a moment of crisis," which was now twenty-one years ago.
In his memorial, Zhuge Liang urged Liu Shan to rely on loyal ministers like Guo Youzhi, Fei Yi, Dong Yun, and Xiang Chong, to "draw near to worthy officials and keep petty men at a distance," and to "seek out good counsel and accept wise words" (to seek and adopt all beneficial advice).
Finally, he used the phrase "Now I am about to depart, shedding tears as I present this memorial, not knowing what I am saying" to express his excitement before the great battle. He left behind over a hundred civil and military officials, including Guo Youzhi and Xiang Chong, to manage Shu's governance and military affairs, then led generals Wei Yan and Wang Ping, marching triumphantly toward Hanzhong.
Later, people used the idiom "buzhi suoyun" to describe speech that is confused or vague.
Source: *Memorial on Sending Out the Troops* by Zhuge Liang (Three Kingdoms Period, Shu Han)
Meaning of the Idiom: Later, the Chinese idiom "不知所云" came to describe how speech is confused or vague.