The Darkened Camp and the Trench

From C4.28, The Iranians and Turanians Fight. It illustrates C4.28.19–29:

C4.28.19
He had a trench dug on the road that facedTuran’s encampment, where its troops were placed.
C4.28.20
He gave command: “Let not a fire appear;Let not the sound of bells reach any ear.”
C4.28.21
Then Khosrow chose brave horsemen from his side,And placed them under Rostam as their guide.
C4.28.22
He chose another force from Iran’s line,All armed and ready for the Shah’s design.
C4.28.23
He placed them under Tus, the army’s head,And sent them toward the hills with ordered tread.
C4.28.24
The matchless Rostam took the level plain,While Tus moved toward the heights with all his train.
C4.28.25
He ordered: “Take your forces far afield;To left and right divide them, spear and shield.
C4.28.26
Take plain and meadow; let no scouts appear,Nor candles shine, nor lamps betray you here.
C4.28.27
If through the dark Afrasiab should sweep,And strike our camp while men are lost in sleep,
C4.28.28
Our troops shall strike his rear and there engage;Then he shall be a hawk shut in a cage.”
C4.28.29
The trench in front, the army to its rear;The Shah stood there, his war-elephants near.