Ts‘ao Kung takes 和 as referring to the 和門 or main gate of the military camp. This, Tu Mu tells us, was formed with a couple of flags hung across. [Cf. Chou Li, ch. xxvii. fol. 31 of the Imperial edition: 直旌門.] 交和 would then mean “setting up his 和門 opposite that of the enemy.” But Chia Lin’s explanation, which has been adopted above, is on the whole simpler and better. Chang Yü, while following Ts‘ao Kung, adds that the words may also be taken to mean “the establishment of harmony and confidence between the higher and lower ranks before venturing into the field;” and he quotes a saying of Wu Tzŭ (chap. 1 ad init.): “Without harmony in the State, no military expedition can be undertaken; without harmony in the army, no battle array can be formed.” In the historical romance 東周列國, chap. 75, Sun Tzŭ himself is represented as saying to 伍員 Wu Yüan: 大凡行兵之法先除內患然後方可外征 “As a general rule, those who are waging war should get rid of all domestic troubles before proceeding to attack the external foe.” 舍 is defined as 止. It here conveys the notion of encamping after having taken the field.
3. 莫難於軍爭軍爭之難者以迂爲直以患爲利
After that, comes tactical manœuvring, than which there is nothing more difficult.
I have departed slightly from the traditional interpretation of Ts‘ao Kung, who says: 從始受命至於交和軍爭難也 “From the time of receiving the sovereign’s instructions until our encampment over against the enemy, the tactics to be pursued are most difficult.” It seems to me that the 軍爭 tactics or manœuvres can hardly be said to begin until the army has sallied forth and encamped, and Ch‘ên Hao’s note gives colour to this view: “For levying, concentrating, harmonising and intrenching an army, there are plenty of old rules which will serve. The real difficulty comes when we engage in tactical operations.” Tu Yu also observes that “the great difficulty is to be beforehand with the enemy in seizing favourable positions.”
The difficulty of tactical manœuvring consists in turning the devious into the direct, and misfortune into gain.
以迂爲直 is one of those highly condensed and somewhat enigmatical expressions of which Sun Tzŭ is so fond. This is how it is explained by Ts‘ao Kung: 示以遠速其道里先敵至也 “Make it appear that you are a long way off, then cover the distance rapidly and arrive on the scene before your opponent.” Tu Mu says: “Hoodwink the enemy, so that he may be remiss and leisurely while you are dashing along with the utmost speed.” Ho Shih gives a slightly different turn to the sentence: “Although you may have difficult ground to traverse and natural obstacles to encounter, this is a drawback which can be turned into actual advantage by celerity of movement.” Signal examples of this saying are afforded by the two famous passages across the Alps—that of Hannibal, which laid Italy at his mercy, and that of Napoleon two thousand years later, which resulted in the great victory of Marengo.
4. 故迂其途而誘之以利後人發先人至此知迂直之計者也
Thus, to take a long and circuitous route, after enticing the enemy out of the way, and though starting after him, to contrive to reach the goal before him, shows knowledge of the artifice of deviation.
Chia Lin understands 途 as the enemy’s line of march, thus: “If our adversary’s course is really a short one, and we can manage to divert him from it (迂之) either by simulating weakness or by holding out some small advantage, we shall be able to beat him in the race for good positions.” This is quite a defensible view, though not adopted by any other commentator. 人 of course = 敵, and 後 and 先 are to be taken as verbs. Tu Mu cites the famous march of 趙奢 Chao Shê in 270 B.C. to relieve the town of 閼與 O-yü, which was closely invested by a 秦 Ch‘in army. [It should be noted that the above is the correct pronunciation of 閼與, as given in the commentary on the Ch‘ien Han Shu, ch. 34. Giles’ dictionary gives “Yü-yü,” and Chavannes, I know not on what authority, prefers to write “Yen-yü.” The name is omitted altogether from Playfair’s “Cities and Towns.”] The King of Chao first consulted 廉頗 Lien P‘o on the advisability of attempting a relief, but the latter thought the distance too great, and the intervening country too rugged and difficult. His Majesty then turned to Chao Shê, who fully admitted the hazardous nature of the march, but finally said: “We shall be like two rats fighting in a hole—and the pluckier one will win!” So he left the capital with his army, but had only gone a distance of 30 li when he stopped and began throwing up intrenchments. For 28 days he continued strengthening his fortifications, and took care that spies should carry the intelligence to the enemy. The Ch‘in general was overjoyed, and attributed his adversary’s tardiness to the fact that the beleaguered city was in the Han State, and thus not actually part of Chao territory. But the spies had no sooner departed than Chao Shê began a forced march lasting for two days and one night, and arrived on the scene of action with such astonishing rapidity that he was able to occupy a commanding position on the 北山 “North hill” before the enemy had got wind of his movements. A crushing defeat followed for the Ch‘in forces, who were obliged to raise the siege of O-yü in all haste and retreat across the border. [See 史記, chap. 81.]
5. 故軍爭爲利衆爭爲危