— this is the art of studying circumstances.
I have not attempted a uniform rendering of the four phrases 治氣, 治心, 治力 and 治變, though 治 really bears the same meaning in each case. It is to be taken, I think, not in the sense of “to govern” or “control,” but rather, as K‘ang Hsi defines it, = 簡習 “to examine and practise,” hence “look after,” “keep a watchful eye upon.” We may find an example of this use in the Chou Li, XVIII. fol. 46: 治其大禮. Sun Tzŭ has not told us to control or restrain the quality which he calls 氣, but only to observe the time at which it is strongest. As for 心, it is important to remember that in the present context it can only mean “presence of mind.” To speak of “controlling presence of mind” is absurd, and Capt. Calthrop’s “to have the heart under control” is hardly less so. The whole process recommended here is that of VI. § 2: 致人而不致於人.
33. It is a military axiom not to advance uphill against the enemy, nor to oppose him when he comes downhill.
The Yü Lan reads 倍 for 背.
34. Do not pursue an enemy who simulates flight; do not attack soldiers whose temper is keen.
35. Do not swallow bait offered by the enemy.
Li Ch‘üan and Tu Mu, with extraordinary inability to see a metaphor, take these words quite literally of food and drink that have been poisoned by the enemy. Ch‘ên Hao and Chang Yü carefully point out that the saying has a wider application. The T‘ung Tien reads 貪 “to covet” instead of 食. The similarity of the two characters sufficiently accounts for the mistake.
Do not interfere with an army that is returning home.
The commentators explain this rather singular piece of advice by saying that a man whose heart is set on returning home will fight to the death against any attempt to bar his way, and is therefore too dangerous an opponent to be tackled. Chang Yü quotes the words of Han Hsin: 從思東歸之士何所不克 “Invincible is the soldier who hath his desire and returneth homewards.” A marvellous tale is told of