Jiuzhou is a city located in China. While the specific geographical details of the modern city are not provided in the source material, the term "zhou" (州) historically served as the largest Chinese territorial division prior to the Tang dynasty.
The concept of "Nine Provinces," which relates to the administrative division of "zhou," has been used since ancient Chinese histories to refer to territorial divisions or islands during the Xia and Shang dynasties. Over time, these regions have come to symbolically represent China. Although the definition dates back to the Spring and Autumn and Warring States periods, the Nine Provinces were not treated as actual administrative regions until the Eastern Han dynasty.