19. 兵之情主速乘人之不及由不虞之道攻其所不戒也
Rapidity is the essence of war:
兵之情 means “the conditions of war,” not, as Capt. Calthrop says, “the spirit of the troops.” According to Tu Mu, 此統言兵之情狀 “this is a summary of leading principles in warfare,” and he adds: 此乃兵之深情將之至事也 “These are the profoundest truths of military science, and the chief business of the general.” The following anecdotes, told by Ho Shih, show the importance attached to speed by two of China’s greatest generals. In 227 A.D., 孟達 Mêng Ta, governor of 新城 Hsin-ch‘êng under the Wei Emperor Wên Ti, was meditating defection to the House of Shu, and had entered into correspondence with Chu-ko Liang, Prime Minister of that State. The Wei general Ssŭ-ma I was then military governor of 宛 Wan, and getting wind of Mêng Ta’s treachery, he at once set off with an army to anticipate his revolt, having previously cajoled him by a specious message of friendly import. Ssŭ-ma’s officers came to him and said: “If Mêng Ta has leagued himself with Wu and Shu, the matter should be thoroughly investigated before we make a move.” Ssŭ-ma I replied: “Mêng Ta is an unprincipled man, and we ought to go and punish him at once, while he is still wavering and before he has thrown off the mask.” Then, by a series of forced marches, he brought his army under the walls of Hsin-ch‘êng within the space of eight days. Now Mêng Ta had previously said in a letter to Chu-ko Liang: “Wan is 1200 li from here. When the news of my revolt reaches Ssŭ-ma I, he will at once inform his Imperial Master, but it will be a whole month before any steps can be taken, and by that time my city will be well fortified. Besides, Ssŭ-ma I is sure not to come himself, and the generals that will be sent against us are not worth troubling about.” The next letter, however, was filled with consternation: “Though only eight days have passed since I threw off my allegiance, an army is already at the city-gates. What miraculous rapidity is this!” A fortnight later, Hsin-ch‘êng had fallen and Mêng Ta had lost his head. [See Chin Shu, ch. 1, f. 3.] In 621 A.D., Li Ching was sent from 夔州 K‘uei-chou in Ssŭ-ch‘uan to reduce the successful rebel 蕭銑 Hsiao Hsien, who had set up as Emperor at the modern 荆州 Ching-chou Fu in Hupeh. It was autumn, and the Yangtsze being then in flood, Hsiao Hsien never dreamt that his adversary would venture to come down through the gorges, and consequently made no preparations. But Li Ching embarked his army without loss of time, and was just about to start when the other generals implored him to postpone his departure until the river was in a less dangerous state for navigation. Li Ching replied: “To the soldier, overwhelming speed is of paramount importance, and he must never miss opportunities. Now is the time to strike, before Hsiao Hsien even knows that we have got an army together. If we seize the present moment when the river is in flood, we shall appear before his capital with startling suddenness, like the thunder which is heard before you have time to stop your ears against it. [See [VII, § 19], note.] This is the great principle in war. Even if he gets to know of our approach, he will have to levy his soldiers in such a hurry that they will not be fit to oppose us. Thus the full fruits of victory will be ours.” All came about as he predicted, and Hsiao Hsien was obliged to surrender, nobly stipulating that his people should be spared and he alone suffer the penalty of death. [See Hsin T‘ang Shu, ch. 93, f. 1 vo.]
take advantage of the enemy’s unreadiness, make your way by unexpected routes, and attack unguarded spots.
20. 凡爲客之道深入則專主人不克
The following are the principles to be observed by an invading force: The further you penetrate into a country, the greater will be the solidarity of your troops, and thus the defenders will not prevail against you.
21. 掠於饒野三軍足食
Make forays in fertile country in order to supply your army with food.
Cf. supra, [§ 13]. Li Ch‘üan does not venture on a note here.
22. 謹養而勿勞併氣積力運兵計謀爲不可測