Correct
不宣而战
/ bù xuān ér zhàn /
Strokes
Definition
open hostilities without declaring war/start an undeclared war
Example
Definition
start an undeclared war; launch the war without the formal declaration
1
Dírén
敌人
bù
不
xuān
宣
érzhàn
而战
。
The enemy attacked without a warning.