乘敌不备 [
chéng dí bú bèi]
take the enemy unawares
take advantage of the enemy's unpreparedness
- 孟获回营,拖走所有船只,据守沪水南岸,阻止蜀军渡河。诸葛亮乘敌不备,从敌人不设防的下流偷渡过河,并袭击了孟获的粮仓。
When Meng Huo went back to the army camp, he removed all the boats from the Lu River to prevent the Shu army from advancing across the river and based himself on the southern bank.