ss. 4 Ts`ao Kung gives an interesting
illustration from his own experience. When invading the
territory of Hsu-chou, he ignored the city of 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 Yu says: "No town should be attacked which, if taken,
cannot be held, or if left alone, will not cause any trouble."
Hsun Ying, when urged to attack Pi-yang, replied: "The city is
small and well-fortified; even if I succeed intaking it, it 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
maneuvers. He said: "It is a great mistake to waste men in
taking a town when the same expenditure of soldiers will gain a
province." [1] ]

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 Tzu (quoted by Tu Mu) is moved to
exclaim: "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.]

4. The general who thoroughly understands the advantages
that accompany variation of tactics knows how to handle his
troops.
5. 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.

[Literally, "get the advantage of the ground," which means
not only securing good positions, but availing oneself of natural
advantages in every possible way. Chang Yu says: "Every kind of
ground is characterized by certain natural features, and also
gives scope for a certain variability of plan. How it is
possible to turn these natural features to account unless
topographical knowledge is supplemented by versatility of mind?"]

6. So, the student of war who is unversed in the art of war
of varying his plans, even though he be acquainted with the Five
Advantages, will fail to make the best use of his men.

[Chia Lin tells us tha