Okayama Prefecture contains the administrative territorial entity Mimasaka
History
Prior to the Meiji Restoration of 1868, the area of present-day Okayama Prefecture was divided between Bitchū, Bizen and Mimasaka Provinces. Okayama Prefecture was formed and named in 1871 as part of the large-scale administrative reforms of the early Meiji period (1868–1912), and the borders of the prefecture were set in 1876.
contains comprises includes encompasses incorporates