Jingzhou was not a single walled city. It was a Han province. Liu Biao’s political center was long at Xiangyang. Jiangling, in Nan commandery, was the military point on the river. The modern city called Jingzhou corresponds mainly to Jiangling, not to the whole province.
In 208 Liu Biao died and Liu Cong surrendered to Cao Cao. Liu Bei fell back through Xiangyang and Changban. After the Red Cliffs, Cao Cao gave up the Jiangling line. Liu Bei gained a foothold in the south, and Sun Quan reached across the Yangzi. When Liu Bei entered Yi, Guan Yu stayed in Jing. In 219 Guan Yu marched on Xiangyang and Fan, and Lü Meng took Jiangling behind him. Nan commandery passed to Sun Quan, and the alliance broke.
The novel turns “borrowed Jingzhou” into a debt that is forever being called in. In the histories Jing is a running partition: whoever held Jiangling and could look north to Xiangyang held the middle Yangzi.