Core city

A core city (中核市, Chūkakushi^?) is a class or category of Japanese city. It is a local administrative division created by the national government. Core cities are delegated many functions normally carried out by prefectural governments, but not as many as designated cities. To become a candidate for core city status, a city must have a population greater than 300,000 and an area greater than 100 square kilometers, although special exceptions may be made by order of the cabinet for cities with populations under 300,000 but over 200,000.

Application for designation is made by a city with the approval of both the city and prefectural assemblies.

The term "core city" was created by the first clause of Article 252, Section 22 of the Local Autonomy Law of Japan.

As of February 2017, 48 cities have been designated core cities:

The following cities have populations greater than 300,000 but have not yet been nominated. (Cities planning to apply for core city status are not shown. ※Special Cities)

...
Wikipedia