入吾彀中 — “To fall into one's trap, snare, or scheme”

The idiom "入吾彀中" (rù wú gòu zhōng) originates from "Tang Zhi Yan" (《唐摭言》), a book by Wang Dingbao from the Five Dynasties period. This book details the imperial examination system and miscellaneous affairs of the Tang Dynasty, often providing more detail than general historical records.

According to the book, one day, Emperor Taizong of Tang (Li Shimin, the second son of Emperor Gaozu Li Yuan) secretly went to inspect the Imperial Censorate (御史府), where the imperial examinations for jinshi were held. When he saw numerous newly successful jinshi candidates emerging in a continuous stream, he remarked with great satisfaction, "天下英雄，人吾彀中矣！" (All the heroes under heaven have entered my snare!) This statement essentially meant, "All the promising young talents in the realm have now fallen into my control/trap!"

Li Shimin was a founding father of the Tang Dynasty, renowned for his literary and martial prowess. After ascending the throne, he achieved a great unification in Chinese history, and his prestige extended far beyond its borders. He was not only a brilliant strategist but also adept at using political maneuvering in his personal conduct; otherwise, he would not have casually uttered such a phrase as "入吾彀中".

When used, this idiom typically describes situations that are not entirely straightforward or honorable. It refers to employing various means of winning people over, setting up elaborate schemes, or laying traps to achieve one's objectives. It can be used as "入吾彀中" (into my snare), "入他彀中" (into his snare), or "入其彀中" (into their snare).