The first chapter of The Art of War says: “War is the way of deception (兵者，诡道也). So when able, appear unable. When active, appear inactive. When near, appear far. When far, appear near.”
It continues: “Offer a gain to lure him. Create disorder and take him. When he is full, prepare for him. Where he is strong, avoid him. Where he is angry, provoke him. Where he is humble, make him proud. When he is at ease, wear him down. When he is united, divide him. Attack where he is not prepared. Appear where he does not expect it.”