Wang Yang swept his chopsticks across the table, pushing the plates, dishes, cups, and bowls toward the four cardinal directions, arranging them like scattered cities. He said calmly:
"First, let us discuss the strategic points in the west.
There are two strategic points in the west. The first is Jianping.
Jianping lies north of Wu Gorge, with towering peaks at its back and the great river to its south. Any force from the upstream garrisons of Shu seeking to descend upon Jingzhou must pass through it. It commands the spine and grips the throat.
Thus the Wu general Wu Yan said of the Jin troops in Shu, 'Until Jianping falls, they will never dare cross the river,' because it could cut off the Shu army's retreat.
It is like an eye on a Go board: secure it, and your position opens; lose it, and your position chokes.
Along the Yangtze River, the most important of these eyes can be counted on ten fingers.
Hold the strategic point at Xiakou, and the thrust eastward along the Han River is checked halfway;
Control the throat at Guabu, and the forces descending westward along the Chuhe River are trapped among the islets;
Occupy the rocky promontory at Caishi, and troops invading southward from Liyang cannot fly across the river; (During Hou Jing's rebellion under the Southern Liang, Yang Kan proposed defending Caishi. Unfortunately, the Imperial Court rejected his advice. Later, improvised deployments and hurried changes of garrison opened a gap, allowing Hou Jing to cross.)
Lock down the passage at Jianping, and armies descending eastward from Shuzhong cannot ride the current! (Sichuan lies west of Jingzhou, upstream on the Yangtze River. Thus an attack from Sichuan toward Jingzhou follows the current downstream, giving naval forces an advantage. This is also called descending eastward.