Chengjia, also known as the Cheng dynasty or Great Cheng, was a self-proclaimed empire established in 25 AD by Gongsun Shu. It emerged following the collapse of the Xin dynasty and served as a significant rival to the Eastern Han dynasty founded by Emperor Guangwu during the same year.
The empire was based in the Sichuan Basin with its capital located at Chengdu. At its height, Chengjia encompassed a vast territory including modern-day Sichuan, Chongqing, Guizhou, Yunnan, and southern Shaanxi, housing approximately 7% of China's population. It was recognized as the most dangerous rival to the Eastern Han and remained the last separatist regime in China to be conquered by the dynasty, falling in 36 AD.