Cf. III. § 4. Ts‘ao Kung gives an interesting illustration from his own experience. When invading the territory of 徐州 Hsü-chou, he ignored the city of 華費 Hua-pi, which lay directly in his path, and pressed on into the heart of the country. This excellent strategy was rewarded by the subsequent capture of no fewer than fourteen important district cities. Chang Yü says: “No town should be attacked which, if taken, cannot be held, or if left alone, will not cause any trouble.” 荀罃 Hsün Ying, when urged to attack 偪陽 Pi-yang, replied: “The city is small and well-fortified; even if I succeed in taking it, ’t will be no great feat of arms; whereas if I fail, I shall make myself a laughing-stock.” In the seventeenth century, sieges still formed a large proportion of war. It was Turenne who directed attention to the importance of marches, countermarches and manœuvres. He said: “It is a great mistake to waste men in taking a town when the same expenditure of soldiers will gain a province.”[173] positions which must not be contested, commands of the sovereign which must not be obeyed. This is a hard saying for the Chinese, with their reverence for authority, and Wei Liao Tzŭ (quoted by Tu Mu) is moved to exclaim: 兵者凶器也爭者逆德也將者死官也 “Weapons are baleful instruments, strife is antagonistic to virtue, a military commander is the negation of civil order!” The unpalatable fact remains, however, that even Imperial wishes must be subordinated to military necessity. Cf. III. § 17. (5), X. § 23. The _T‘ung Tien_ has 將在軍 before 君命, etc. This is a gloss on the words by Chu-ko Liang, which being repeated by Tu Yu became incorporated with the text. Chang Yü thinks that these five precepts are the 五利 referred to in § 6. Another theory is that the mysterious 九變 are here enumerated, starting with 圮地無舍 and ending at 地有所不爭, while the final clause 君命有所不受 embraces and as it were sums up all the nine. Thus Ho Shih says: “Even if it be your sovereign’s command to encamp in difficult country, linger in isolated positions, etc., you must not do so.” The theory is perhaps a little too ingenious to be accepted with confidence. 4. 故將通於九變之利者知用兵矣 The general who thoroughly understands the advantages that accompany variation of tactics knows how to handle his troops. Before 利 in the original text there is a 地 which is obviously not required. 5. 將不通於九變之利者雖知地形不能得地之利矣 The general who does not understand these, may be well acquainted with the configuration of the country, yet he will not be able to turn his knowledge to practical account.