出其不意，攻其不備

出其不意，攻其不备
chūqíbùyì,gōngqíbùbèi
to catch an enemy off guard with a surprise attack (idiom, from Sunzi's "The Art of War" 孫子兵法 Sūnzǐ Bīngfǎ)

CEDICT

Entry Composition

1 出其不意 chūqíbùyì to do sth when least expected (idiom); to catch sb off guard
2 攻其不備 gōngqíbùbèi see 出其不意，攻其不備，攻其不备 chūqíbùyì,gōngqíbùbèi