and Earth, unending as the flow of rivers and streams; like the sun and
moon, they end but to begin anew; like the four seasons, they pass away
but to return once more.
[Tu Yu and Chang Yu understand this of the permutations of _ch’i_ and
_cheng_. But at present Sun Tzŭ is not speaking of _cheng_ at all,
unless, indeed, we suppose with Cheng Yu-hsien that a clause relating
to it has fallen out of the text. Of course, as has already been
pointed out, the two are so inextricably interwoven in all military
operations, that they cannot really be considered apart. Here we simply
have an expression, in figurative language, of the almost infinite
resource of a great leader.]