圍城打援 [ㄨㄟˊ ㄔㄥˊ ㄉㄚˇ ㄩㄢˊ; wei2 cheng2 da3 yuan2] to besiege and strike the relief force (idiom); strategy of surrounding a unit to entice the enemy to reinforce, then striking the new troops ◄ ►