里应外合

Pronunciation: lǐ yìng wài hé Literal meaning: Inside support outside cooperation

Origin & Usage

Those inside (里) answer (应) and those outside (外) join them (合) — the pincer in which a siege is broken by a gate opened from within. It appears in Yuan drama and belongs to the vocabulary of military plotting. Modern use has kept the structure and lost the walls: it now describes any operation requiring a person on the inside, and it is as likely to describe fraud or a leak as a legitimate coordination. Whether it is praise or accusation depends entirely on who is speaking.

Examples

English: "The plan was successful because the team coordinated perfectly with external partners."

Chinese: 这个计划之所以成功，是因为团队里应外合。