8. Variation in Tactics
The heading means literally "The Nine Variations," but as Sun Tzu does not appear to enumerate these, and as, indeed, he has already told us (V SS. 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 we ought to very our tactics to the utmost degree.... I do not know what Ts`ao Kung makes these Nine Variations out to be, but it has been suggested that they are connected with the Nine Situations" of chapt. XI. This is the view adopted by Chang Yu. 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.
Repeated from VII. ss. 1, where it is certainly more in place. It may have been interpolated here merely in order to supply a beginning to the chapter.