《新五代史·列传·周臣传第十九》
先从防备少的地方骚扰，防备束就骚扰西，防备西就骚扰束，他们一定会奔走救援防备差的地方，奔走救援的时候，可以知道对方的虚实、兵众的强弱，攻击对方虚弱之处，就所向无敌了。
从少备处先挠之，备东则挠西，备西则挠东，彼必奔走以救其弊，奔走之间，可以知彼之虚实、众之强弱，攻虚击弱，则所向无前矣。
Start with harassing the less guarded places; harass the east if they are guarding the west, and harass the west if they are guarding the east. They will definitely rush to rescue the poorly guarded places. When they rush to their rescue, you can learn the truth and the strengths and weaknesses of their troops. Attacking the weak points of the enemy, you will be invincible.