the enemy's
march."]

The appearance of a number of screens in the midst of thick grass
means that the enemy wants to make us suspicious.

[Tu Yu's explanation, borrowed from Ts`ao Kung's, is as
follows: "The presence of a number of screens or sheds in the
midst of thick vegetation is a sure sign that the enemy has fled
and, fearing pursuit, has constructed these hiding-places in
order to make us suspect an ambush." It appears that these
"screens" were hastily knotted together out of any long grass
which the retreating enemy happened to come across.]

22. The rising of birds in their flight is the sign of an
ambuscade.

[Chang Yu's explanation is doubtless right: "When birds
that are flying along in a straight line suddenly shoot upwards,
it means that soldiers are in ambush at the spot beneath."]

Startled beasts indicate that a sudden attack is coming.
23. When there is dust rising in a high column, it is the
sign of chariots advancing; when the dust is low, but spread over
a wide area, it betokens the approach of infantry.

["High and sharp," or rising to a peak, is of course
somewhat exaggerated as applied to dust. The commentators
explain the phenomenon by saying that horses and chariots, being
heavier than men, raise more dust, and also follow one another in
the same wheel-track, whereas foot-soldiers would be marching in
ranks, many abreast. According to Chang Yu, "every army on the
march must have scouts some way in advance, who on sighting dust
raised by the enemy, will gallop back and report it to the
commander-in-chief." Cf. Gen. Baden-Powell: "As you move along,
say, in a hostile country, your eyes should be looking afar for
the enemy or any signs of him: figures, dust rising, birds
getting up, glitter of arms, etc." [1] ]

When it branches out in different directions, it shows that
parties have been sent to collect firewood. A few clouds of dust
moving to and fro signify that the army is encamping.

[Chang Yu says: "In apportioning the defenses for a
cantonment, light horse will be sent out to survey the position
and ascertain the weak and strong points all along its
circumference. Hence the small quantity of dust and its
motion."]

24. Humble words and increased preparations are signs that
the enemy is about to advance.

["As though they stood in great fear of us," says Tu Mu.
"Their object is to make us contemptuous