They were first instituted as a regular form of administrative division of China's Tang Empire, but were later adopted in Vietnam, Japan and Korea.
The Japanese language uses the Chinese character: (i) as a part of words, such as government (政府, seifu), shogunate (幕府, bakufu), Cabinet Office (内閣府, naikakufu), and legislature (立法府, rippō-fu), or (ii) as the name of a category of prefectures.
One of the earlier uses of fu as part of the name of an administrative division was the Protectorate of the Western Regions (西域都護府, Xīyù Dūhù Fǔ) of the Han Empire in 60 BC.
After the end of the Qing dynasty in 1912, the Republic of China abolished fu in order to streamline administrative divisions, recategorizing them into counties or cities.
By the end of 1868, 10 fu had been established: Kyoto, Hakodate, Osaka, Nagasaki, Edo (later Tokyo), Kanagawa, Watarai, Nara, Echigo (later Niigata) and Kōfu.
Due to some prefectures gaining non-urban land or being amalgamated into other territories in 1869, three remained: Kyoto-fu, Osaka-fu and Tokyo-fu.
One of these changes was to split the Eight Provinces of Korea into 23 bu: Andong, Chuncheon, Chungju, Daegu, Dongnae, Gangneung, Gongju, Haeju, Hamhŭng, Hanseong, Hongju, Incheon, Jeju, Jeonju, Jinju, Kaesŏng, Kanggye, Kapsan, Kyŏngsŏng, Naju, Namwon, P'yŏngyang and Ŭiju.
On 1 April 1914, twelve bu were created: Seoul (then Gyeongseong-bu (京城府, Keijō-fu)), Incheon, Gunsan, Mokpo, Daegu, Busan, Masan, Pyongyang, Chinnampo, Sinuiju, Wonsan and Chongjin.
Between 1930 and 1944, 10 more were added by the Japanese government: Kaesong and Hamhung in 1930, followed by Daejeon, Jeonju and Gwangju in 1935, Rason (1936), Haeju (1938), Jinju (1939), Kimchaek (1941) and Hungnam (1944).