虛實篇 NO.7：

夫兵形象水，水之形，避高而趨下，兵之形，避實而擊虛。

水因地而制流，兵因敵而制勝。

故兵無常勢，水無常形。

能因敵變化而取勝者，謂之神。

故五行無常勝，四時無常位，日有短長，月有死生。

這句啥意思：

兵的性態就象水一樣，水流動時是避開高處流向低處，用兵取勝的關鍵是避開設防嚴密實力強大的敵人而攻擊其薄弱環節；

水根據地勢來決定流向，軍隊根據敵情來采取制勝的方略。

所以用兵作戰沒有一成不變的態勢，正如流水沒有固定的形狀和去向。

能夠根據敵情的變化而取勝的，就叫做用兵如神。

金、木、水、火、土這五行相生相克，沒有哪一個常勝；四季相繼相代，沒有哪一個固定不移，白天的時間有長有短，月亮有圓也有缺。萬物皆處于流變狀態。

英文這么說：

Military tactics are like unto water; for water in its natural course runs away from high places and hastens downwards. So in war, the way is to avoid what is strong and to strike at what is weak.

Water shapes its course according to the nature of the ground over which it flows; the soldier works out his victory in relation to the foe whom he is facing.
Therefore, just as water retains no constant shape,so in warfare there are no constant conditions.
He who can modify his tactics in relation to his opponent and thereby succeed in winning, may be called a heaven-born captain.
The five elements (water, fire, wood, metal, earth)are not always equally predominant; the four seasons make way for each other in turn. There are short days and long;the moon has its periods of waning and waxing.

《五行簡介》