"In war," says Chang Yu, "if a spirit of anger can be made to pervade all ranks of an army at one and the same time, its onset will be irresistible. Now the spirit of the enemy's soldiers will be keenest when they have newly arrived on the scene, and it is therefore our cue not to fight at once, but to wait until their ardor and enthusiasm have worn off, and then strike. It is in this way that they may be robbed of their keen spirit." Li Ch`uan and others tell an anecdote (to be found in the TSO CHUAN, year 10, ss. 1) of Ts`ao Kuei, a protege of Duke Chuang of Lu. The latter State was attacked by Ch`i, and the duke was about to join battle at Ch`ang-cho, after the first roll of the enemy's drums, when Ts`ao said: "Not just yet." Only after their drums had beaten for the third time, did he give the word for attack. Then they fought, and the men of Ch`i were utterly defeated. Questioned afterwards by the Duke as to the meaning of his delay, Ts`ao Kuei replied: "In battle, a courageous spirit is everything. Now the first roll of the drum tends to create this spirit, but with the second it is already on the wane, and after the third it is gone altogether. I attacked when their spirit was gone and ours was at its height. Hence our victory." Wu Tzu (chap. 4) puts "spirit" first among the "four important influences" in war, and continues: "The value of a whole army—a mighty host of a million men—is dependent on one man alone: such is the influence of spirit!"
Chang Yu says: "Presence of mind is the general's most important asset. It is the quality which enables him to discipline disorder and to inspire courage into the panic stricken." The great general Li Ching (A.D. 571-649) has a saying: "Attacking does not merely consist in assaulting walled cities or striking at an army in battle array; it must include the art of assailing the enemy's mental equilibrium."