Subprefecture of Japan (支庁, shichō) are a Japanese form of self-government which focuses on local issues below the prefectural level. It acts as part of the greater administration of the state and as part of a self-government system.
They were given a definite form in 1878 (Meiji 11).
The Meiji government established the sub-prefecture (郡, -gun) as an administrative unit.
Certain prefectures of Japan are now, or once were, divided into subprefectures. The subprefecture is the jurisdiction surrounding a "branch office" of the prefectural government. Normally, the area of a subprefecture consists of a few to a dozen cities, towns, and/or villages. Subprefectures are formed to provide services of the prefectural government in geographically remote areas. They are usually not used in postal addresses.
In addition, in 1907 Japan formed Karafuto Prefecture to govern the island of Sakhalin. Karafuto was divided into four subprefectures: Toyohara (in present-day Yuzhno-Sakhalinsk), Maoka (in present-day Kholmsk), Esutoru (in present-day Uglegorsk) and Shikuka (in present-day Makarov).
A number of islands gained by Japan in the Treaty of Versailles were placed under the direction of a South Pacific Prefecture (南洋庁, Nan'yōchō) from 1922 to 1945. This was divided into six subprefectures, on the islands of Saipan, Yap, Palau, Truk, Pohnpei and Jaluit. In November 1943, the six subprefectures were merged into "eastern," "western" and "northern" subprefectures, which remained in place until the Surrender of Japan in 1945.
Taiwan during Japanese rule initially had its prefectures – ken (県), later termed shū (州) and chō (庁) – subdivided into shichō. Most of the later subprefectures were named gun (郡, also "districts").
Some English texts translate "sub-prefecture" differently, using it instead for the chō of Taiwan, which were remote prefectures that were much less populated, once considered "sub-", or "lesser", prefectures, i.e., Hōko (the Pescadores), Karenkō (Hualien) and Taitō (Taitung). The offshore Hōko was home to the last two remaining subprefectures named shichō: Makō (馬公支廳) and Mōan (望安支廳).
(See: Political divisions of Taiwan (1895–1945))