While these authorities were granted by statute during the US-led occupation and again in 1975, they could be unilaterally revoked by the National Diet; similar measures against other municipalities would require a constitutional amendment.

[citation needed] In 1998, the National Diet passed a revision of the Local Autonomy Law (effective in the year 2000) that implemented the conclusions of the Final Report on the Tokyo Ward System Reform increasing their fiscal autonomy and established the wards as basic local public entities.

[citation needed] The word "special" distinguishes them from the wards (区, ku) of other major Japanese cities.

[citation needed] On March 15, 1943, as part of wartime totalitarian tightening of controls, Tokyo's local autonomy (elected council and mayor) under the Imperial municipal code was eliminated by the Tōjō cabinet and the Tokyo city government and (Home ministry appointed) prefectural government merged into a single (appointed) prefectural government;[4] the wards were placed under the direct control of the prefecture.

The postwar reorganization under the US-led occupation authorities democratized the prefectural administrations but did not include the reinstitution of Tokyo City.

Today, each special ward has its own elected mayor (区長, kuchō) and assembly (区議会, kugikai).

In 2000, the National Diet designated the special wards as local public entities (地方公共団体, chihō kōkyō dantai), giving them a legal status similar to cities.

The total population census of the 23 special wards had fallen under 8 million as the postwar economic boom moved people out to suburbs, and then rose as Japan's lengthy stagnation took its toll and property values drastically changed, making residential inner areas up to 10 times less costly than during peak values.

[6] However, prefectures (道府県, -dō/-fu/-ken) where special wards are set up cannot style themselves metropolis (都, -to) as the Local Autonomy Law only allows Tokyo with that status.