Chengdu was the heart of Yi province. Liu Yan and his son Liu Zhang kept a comparatively intact province here. In 211 Liu Bei entered Shu at Liu Zhang’s invitation, then turned against him. In 214 he besieged Chengdu, Liu Zhang surrendered, and Liu Bei became governor of Yi. In 221 he took the imperial title in the city.
Zhuge Liang’s chancellery was here as well. Armies for the south and for the northern expeditions were organized in Chengdu and then sent up to Hanzhong. Jieting and Wuzhangyuan were not fought under the city walls. When the novel lets the stars over Chengdu decide a distant front, that is the novel’s compression.
For Shu Han, Chengdu is the interior: registers, agriculture, and the court. Its northern gate was Hanzhong. What it lost in the east was Jing province.