The Art of War by active 6th century B.C. Sunzi

13. By discovering the enemy’s dispositions and remaining invisible

ourselves, we can keep our forces concentrated, while the enemy’s must be divided. [The conclusion is perhaps not very obvious, but Chang Yu (after Mei Yao-ch’en) rightly explains it thus: "If the enemy’s dispositions are visible, we can make for him in one body; whereas, our own dispositions being kept secret, the enemy will be obliged to divide his forces in order to guard against attack from every quarter."]