以夷制夷

1. • to use foreigners to subdue foreigners (idiom) let the barbarians fight it out among themselves (traditional policy of successive dynasties)
2. • Use Western science and technology to counter imperialist encroachment. (late Qing modernizing slogan)

Character by character

• 以(yǐ)use
• 夷(yí)barbarians
• 制(zhì)system
• 夷(yí)barbarians