里应外合

裡應外合
lǐyìngwàihé
idiom

Meanings

  1. 1 to coordinate outside and inside attacks
  2. 2 insiders and outsiders acting in concert (often to pull off a scheme)

Examples

Díjūn lǐ yìng wài hé, gōngpò le chéngchí.
The enemy coordinated inside and outside forces and breached the city.
Zhè cì dàoqiè míngxiǎn shì lǐ yìng wài hé.
This theft was clearly an inside job with outside help.
Xiāoshòu hé shìchǎng bù lǐ yìng wài hé, cái néng bǎ chǎnpǐn tuī chūqù.
Sales and marketing have to work hand in glove to get the product out there.

Tips

history
From Yang Zi's () Yuan drama 《》: Zhao, Han, and Wei 'plotted together, coordinating inside and outside' — 里应外合 — to flood and rout the army. Originally a military tactics phrase.
usage
Usually about schemes: insiders open the gate while outsiders attack, or a staff member tips off thieves. Can also be used neutrally for legitimate team coordination (field team + HQ). = insider responds; = outsider combines forces.

Stroke Order

yīng
wài