Circuit (political division)

A circuit ( ; Chinese: dào; Japanese: dō) was a historical political division of Tang China and Japan and Korea. In Korean, the same word () is translated as "province".
China.
Emperor Taizong divided China into parts which were called "circuits".
The organization of government and geography in Tang China were merged into provinces ("dao" ) which were ten natural regions. In part, Tang history is about the changing balance between the provinces and a strong central government.
Japan.
During the pre-modern era, Japan was divided into a central region and seven provincial regions or "circuits", including
In the mid-19th century, the northern island of Ezo was settled, and renamed .
Hokkaido did not develop as a "circuit" in the traditional way. It became a prefecture. It had a name that was different from the other prefectures because of the suffix "-dō".
Korea.
After the late-10th century, the province ("do") was the main subdivision of Korea.