冒天下之大不韪 — “To defy universal condemnation”

Around 712 BC, two neighboring states, Zheng and Xi, both sharing a common ancestral lineage, fell into conflict over a minor disagreement. The state of Xi, significantly weaker, acted impulsively by dispatching troops to attack the formidable state of Zheng. This rash decision led to a crushing defeat for Xi.

Subsequently, the powerful state of Chu seized the opportunity, profiting from the conflict to annex Xi. It was widely believed that Xi's act of rashly initiating warfare against a stronger opponent was a grave defiance of common sense and universally accepted prudence, which ultimately sealed its fate.