21. Ponder and deliberate before you make a move.
[Chang Yu quotes Wei Liao Tzŭ as saying that we must not break camp until we have gained the resisting power of the enemy and the cleverness of the opposing general. Cf. the "seven comparisons" in I. § 13.]
22. He will conquer who has learnt the artifice of deviation.
[See supra, §§ 3, 4.]
Such is the art of manœuvering.
[With these words, the chapter would naturally come to an end. But there now follows a long appendix in the shape of an extract from an earlier book on War, now lost, but apparently extant at the time when Sun Tzŭ wrote. The style of this fragment is not noticeably different from that of Sun Tzŭ himself, but no commentator raises a doubt as to its genuineness.]
23. The Book of Army Management says:
[It is perhaps significant that none of the earlier commentators give us any information about this work. Mei Yao- Ch’en calls it "an ancient military classic," and Wang Hsi, "an old book on war." Considering the enormous amount of fighting that had gone on for centuries before Sun Tzŭ’s time between the various kingdoms and principalities of China, it is not in itself improbable that a collection of military maxims should have been made and written down at some earlier period.]
On the field of battle,
[Implied, though not actually in the Chinese.]