Yi Province (益州) was a vast administrative region covering the Sichuan Basin and surrounding mountainous areas. Protected by natural barriers and blessed with fertile land, it became the foundation of Liu Bei’s Shu Han kingdom.
Historical significance
Yi Province was established during the Han dynasty, encompassing modern Sichuan Province and Chongqing Municipality. The Sichuan Basin was one of China’s most agriculturally productive regions, supported by the Min and Tuo rivers. The surrounding mountains provided natural defences, making the province difficult to invade.
Under Liu Zhang
Liu Zhang inherited control of Yi Province from his father Liu Yan in 194. Liu Zhang was known for his kindness but lacked the decisiveness needed to maintain power. His officials Zhang Song and Fa Zheng secretly invited Liu Bei to take control, believing Liu Zhang was too weak to defend against external threats.
Liu Bei’s conquest
In 211, Liu Bei entered Yi Province ostensibly to help Liu Zhang defend against Zhang Lu in Hanzhong. However, tensions grew between the two Liu clans. By 214, Liu Bei had turned against Liu Zhang and laid siege to Chengdu. Liu Zhang surrendered, and Liu Bei took control of the province.
Base of Shu Han
Yi Province became the territorial core of Shu Han when Liu Bei declared himself emperor in 221. Zhuge Liang developed the province’s economy, improved agriculture, and organised the military. The province’s isolation protected Shu Han from direct invasion for decades.
Hanzhong and northern defences
In 219, Liu Bei captured Hanzhong Commandery from Cao Cao, securing the northern approaches to Yi Province. This victory allowed Liu Bei to claim the title of King of Hanzhong and provided a base for future northern expeditions.
Fall of Shu
In 263, Deng Ai led Wei forces through the mountainous terrain and reached the Chengdu plain. Liu Shan surrendered without a fight, ending Shu Han’s independence. Yi Province was incorporated into Wei territory, later passing to the Jin dynasty.
Modern region
Today, the region of ancient Yi Province comprises Sichuan Province and Chongqing Municipality. Chengdu and Chongqing remain major cities. The region is known for its distinctive culture, cuisine, and historical sites from the Three Kingdoms period.
References
- Chen Shou, Records of the Three Kingdoms (三国志)
- Fan Ye, Book of the Later Han (后汉书)
- Sima Guang, Zizhi Tongjian (资治通鉴)
- de Crespigny, Rafe. A Biographical Dictionary of Later Han to the Three Kingdoms