一筹莫展 — “To be at one's wits' end”

According to 'History of Song: Biography of Cai Youxue', Cai Youxue, courtesy name Xingzhi, was a native of Ruian, Wenzhou, during the Southern Song Dynasty. He studied diligently from a young age and once apprenticed under the renowned scholar Zhang Fulian. It is said that he later surpassed his teacher, excelling in both talent and writing. During Emperor Guangzong's reign, he served as a Collator of Books.

Later, after Emperor Guangzong's death, Emperor Ningzong ascended the throne. Early in his reign, Emperor Ningzong issued an edict soliciting opinions from his ministers. Cai Youxue submitted a memorial, stating: "Your Majesty, you must accomplish three things to be considered a good emperor. First, be filial to your parents and elders; second, value the virtuous by appointing truly talented individuals to official positions; and third, love the people by being benevolent and generous to all under heaven. To achieve these three things, one must first start with education. However, in recent years, some people have been spreading rumors and slandering good individuals, causing some ministers to fear getting into trouble and thus unable to fully exercise their talents, and also preventing Your Majesty from connecting with most ambitious officials.

Although there are many talented ministers in the court, truly effective solutions have not been put forth." This was expressed as "多士盈庭而一筹莫吐" (Many officials fill the court, yet not a single plan is presented). "Your Majesty, if education is not prioritized and encouraged, and a good learning atmosphere is not established, the consequences will be unimaginable. May Your Majesty consider this carefully."

Based on this story, the phrase "一筹不吐" (unable to present a single plan) evolved into the idiom "一筹莫展," which means to be at one's wits' end, with no solutions in mind.