6. Weak Points and Strong

34

The five elements (water, fire, wood, metal, earth) are not always equally predominant;

That is, as Wang Hsi says: "they predominate alternately."

the four seasons make way for each other in turn.

Literally, "have no invariable seat."

There are short days and long; the moon has its periods of waning and waxing.

Cf. V. ss. 6. The purport of the passage is simply to illustrate the want of fixity in war by the changes constantly taking place in Nature. The comparison is not very happy, however, because the regularity of the phenomena which Sun Tzu mentions is by no means paralleled in war.