advancing.
[Ts’ao Kung explains this as "felling trees to clear a passage," and
Chang Yu says: "Every man sends out scouts to climb high places and
observe the enemy. If a scout sees that the trees of a forest are
moving and shaking, he may know that they are being cut down to clear a
passage for 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.]