How did Sichuan become the Shu-Han kingdom during the Three Kingdoms period?

During the collapse of the Han dynasty at the end of the 2nd century, China descended into chaos, leading to the rise of independent regional powers. Liu Bei, a prominent general who claimed descent from the Han imperial line, occupied the region of Sichuan.123

Following the 220 CE abdication of the last Han emperor to Cao Pi—who established the Wei kingdom in the north—Liu Bei declared himself emperor in 221 CE. By establishing the Shu-Han dynasty with its capital at Chengdu, Liu Bei maintained the political fiction that he was continuing the legitimate Han rule in the southwest.145

His success was significantly aided by his advisor, Zhuge Liang, who helped him organize a large army and establish the state. The Shu-Han kingdom remained a distinct power within the Three Kingdoms period until it was conquered by the Wei in 263/264 CE.632