Taotai

A circuit (Chinese and Japanese: 道; pinyin: dào; rōmaji: dō) was a historical political division of China and is a term for an administrative unit still used in Japan.

Circuits originated in China during the Han dynasty, and were used as a lower tier administrative division, comparable to the county (縣/县, also translated as "districts"), but only to be used in areas in the fringes of the Empire, that were either primarily inhabited 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 Later Jin and Song dynasties, circuits were renamed from dao to lu (路), both of which literally mean "road" or "path". Dao were revived during the Yuan dynasty.

Circuits were demoted to the second-level after the Yuan dynasty established provinces at the very top, and remained there for the next several centuries. Under the Qing, they were overseen by a circuit intendant or tao-tai (Chinese: ; pinyin: dàotái). The circuit intendant of Shanghai was particularly influential.

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