Sun Wu and his family spent several days making a comprehensive and detailed survey of the geographical terrain around Kwai Qiu Bing Fortress. Then, go straight to the next inspection target, the battlefield of Qilu War is dry and dry. Dry season is the general name of the lower reaches of Jishui River, and the area it flows through is mainly in Guangrao County, Shandong Province today. The current water source is a seasonal river in the east of today's Linzi Aihuaishu Village.
During the rainy season, the water is very strong, which is easy to cause flash floods. The flood rushed out of the valley, cut the hard brown-red soil and split a steep river ditch with a depth of tens of meters and a width of more than 20 meters. In the dry season, the stream is cut off, revealing an extremely steep and deep riverbed, which becomes a natural barrier running through the north and south, and it is easy to defend but difficult to attack.