19. Let your plans be dark and impenetrable as night, and when you move, fall like a thunderbolt. [Tu Yu quotes a saying of T’ai Kung which has passed into a proverb: "You cannot shut your ears to the thunder or your eyes to the lighting—so rapid are they." Likewise, an attack should be made so quickly that it cannot be parried.] 20. When you plunder a countryside, let the spoil be divided amongst your men; [Sun Tzŭ wishes to lessen the abuses of indiscriminate plundering by insisting that all booty shall be thrown into a common stock, which may afterwards be fairly divided amongst all.] when you capture new territory, cut it up into allotments for the benefit of the soldiery. [Ch’en Hao says "quarter your soldiers on the land, and let them sow and plant it." It is by acting on this principle, and harvesting the lands they invaded, that the Chinese have succeeded in carrying out some of their most memorable and triumphant expeditions, such as that of Pan Ch’ao who penetrated to the Caspian, and in more recent years, those of Fu-k’ang-an and Tso Tsung-t’ang.] 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.] the spoken word does not carry far enough: hence the institution of gongs and drums. Nor can ordinary objects be seen clearly enough: hence the institution of banners and flags. 24. Gongs and drums, banners and flags, are means whereby the ears and eyes of the host may be focussed on one particular point. [Chang Yu says: "If sight and hearing converge simultaneously on the same object, the evolutions of as many as a million soldiers will be like those of a single man."!]