Chengjia, also known as the Cheng dynasty or Great Cheng, was a self-proclaimed empire established by Gongsun Shu in 25 AD, following the collapse of the Xin dynasty. It emerged in the same year as the Eastern Han dynasty, which was founded by Emperor Guangwu, and the two regimes were rivals.
Chengjia was based in the Sichuan Basin, with its capital at Chengdu. At its height it covered a large area that included modern Sichuan, Chongqing, Guizhou, Yunnan, and southern Shaanxi, and it comprised about 7% of China's population at the time.
Among the rivals of the Eastern Han, Chengjia was regarded as the most dangerous, and it was the last separatist regime in China to be conquered by the Eastern Han, which defeated it in 36 AD.