Aizu domain in the context of "Koku"

Japan is divided into 47 prefectures (都道府県, todōfuken, [todoːɸɯ̥ꜜkeɴ] ), which rank immediately below the national government and form the country's first level of jurisdiction and administrative division. They include 43 prefectures proper (県, ken), two urban prefectures (府, fu: Osaka and Kyoto), one regional prefecture (道, dō: Hokkaidō) and one metropolis (都, to: Tokyo). In 1868, the Meiji Fuhanken sanchisei administration created the first prefectures (urban fu and rural ken) to replace the urban and rural administrators (bugyō, daikan, etc.) in the parts of the country previously controlled directly by the shogunate and a few territories of rebels/shogunate loyalists who had not submitted to the new government such as Aizu/Wakamatsu. In 1871, all remaining feudal domains (han) were also transformed into prefectures, so that prefectures subdivided the whole country. In several waves of territorial consolidation, today's 47 prefectures were formed by the turn of the century. In many instances, these are contiguous with the ancient ritsuryō provinces of Japan.

Each prefecture's chief executive is a directly elected governor (知事, chiji). Ordinances and budgets are enacted by a unicameral assembly (議会, gikai) whose members are elected for four-year terms.