circuit

A circuit ( or ) was a historical political division of China and is a historical and modern administrative unit in Japan. The primary level of administrative division of Korea under the Joseon and in modern North and South Korea employs the same Chinese character as the Chinese and Japanese divisions but, because of its relatively greater importance, is usually translated as province instead. China Circuits originated in China during the Han dynasty and were used as a lower-tier administrative division, comparable to the county (, also translated as "districts"). They were used only in the fringes of the empire, which were either inhabited primarily by non-Han Chinese peoples or too geographically isolated from the rest of the Han centers of power. The system fell into disuse after the collapse of the Western Jin dynasty. The administrative division was revived in 627 when Tang Emperor Taizong made it the highest level administrative division and subdivided China into ten circuits. These were originally meant to be purely geographic and not administrative. Emperor Xuanzong added a further five, and slowly the circuits strengthened their own power until they became powerful regional forces that tore the country apart during the Five Dynasties and Ten Kingdoms period. During the Song and Jin dynasties, circuits (“dao”) were renamed lu, both of which mean "road" or "path".