The heading means literally “The Nine Variations,” but as Sun Tzŭ
does not appear to enumerate these, and as, indeed, he has already
told us (V. §§ 6–11) that such deflections from the ordinary
course are practically innumerable, we have little option but to
follow Wang Hsi, who says that “Nine” stands for an indefinitely
large number. “All it means is that in warfare 當極其變 we ought to
vary our tactics to the utmost degree ... I do not know what Ts‘ao
Kung makes these Nine Variations out to be [the latter’s note is
變其正得其所用九也], but it has been suggested that they are
connected with the Nine Situations”—of chap. XI. This is the view
adopted by Chang Yü: see note on 死地, § 2. The only other
alternative is to suppose that something has been lost—a
supposition to which the unusual shortness of the chapter lends
some weight.