[Mei Yao-ch’en connects this with the foregoing: "Having succeeded in thus dislocating the enemy, they would push forward in order to secure any advantage to be gained; if there was no advantage to be gained, they would remain where they were."] 18. If asked how to cope with a great host of the enemy in orderly array and on the point of marching to the attack, I should say: "Begin by seizing something which your opponent holds dear; then he will be amenable to your will." [Opinions differ as to what Sun Tzŭ had in mind. Ts’ao Kung thinks it is "some strategical advantage on which the enemy is depending." Tu Mu says: "The three things which an enemy is anxious to do, and on the accomplishment of which his success depends, are: (1) to capture our favourable positions; (2) to ravage our cultivated land; (3) to guard his own communications." Our object then must be to thwart his plans in these three directions and thus render him helpless. [Cf. III. § 3.] By boldly seizing the initiative in this way, you at once throw the other side on the defensive.] 19. Rapidity is the essence of war: [According to Tu Mu, "this is a summary of leading principles in warfare," and he adds: "These are the profoundest truths of military science, and the chief business of the general." The following anecdotes, told by Ho Shih, shows the importance attached to speed by two of China’s greatest generals. In 227 A.D., Meng Ta, governor of Hsin-ch’eng under the Wei Emperor Wen 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 Ssu-ma I was then military governor of Wan, and getting wind of Meng 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. Ssu-ma’s officers came to him and said: "If Meng Ta has leagued himself with Wu and Shu, the matter should be thoroughly investigated before we make a move." Ssu-ma I replied: "Meng 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, be brought his army under the walls of Hsin-ch’eng with in a space of eight days. Now Meng Ta had previously said in a letter to Chu-ko Liang: "Wan is 1200 _li_ from here. When the news of my revolt reaches Ssu-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, Ssu-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’eng had fallen and Meng Ta had lost his head. [See _Chin Shu_, ch. 1, f.