After WW2, the reform of Fu and Ken became one of the most important issues of postwar reforms. This was shown obvious in the first part of local autonomy part of the draft of the new constitution proposed by the GHQ (General Headquarters of the Allied Forces) in February 1946 (Showa era 21), which was "Presidents of Fu and Ken, Mayors, Town Mayors, the magistrates of all the local governments which have power to levy taxes, assembly members of Fu and Ken, assembly members of other local government, and other local government officials who are defined by the national assembly shall be elected by the residents through direct popular election." This article survived in the draft of the new constitution proposed by the central government in March 1946 (Showa era 21) as "Presidents of local governments, assembly members of local governments, and other local government officials who are defined by the national law shall be elected by the residents through direct popular election." This article at last became the second paragraph of Article 93 of the Constitution.

The Japanese government started to examine the introduction of the direct election of the chief executives of local governments without waiting the establishment of the new Japanese Constitution. At the first reform of local autonomy system in September 1946 (Showa era 21) which was ahead of the enforcement of the Constitution, the Japanese government revised "Tokyo To Sei" and "Fu Ken Sei" and the chief executives of Tokyo, Hokkaido, Fu, and Ken were come to be elected by the residents through direct election. The revise at this time support democratization by introduction of initiative, establishment of election administration committee, introduction of authority of the assembly members for non confidence resolution, and right of dissolution of assembly to the chief executives. At this first reform of local autonomy system, there was argument in the government whether the revise of the Constitution should be ahead of the reform or the reform should be ahead of the revise of the Constitution. Following the precedent experience that the establishment of local administrative system was ahead of the establishment of Meiji Constitution, the Japanese government took the positive position to the reform of local autonomy and executed the reform of it a half year before the revise of the Constitution.

In addition since there had been no special agency to check the accounting in Ken and Fu and the Board of Audit was responsible for the accounting of national expenditure by Fu and Ken, audit commissioner system was created and came to check the accounting of Fu and Ken. Moreover, since assembly members and alderpersons of local governments had been regarded as the honorary post and had been given only the compensation for the expense necessary for their execution of their responsibilities, they came to be get salary. One of the reasons for these reforms was that local governments were responsible for many complicated administrative works. This shows the importance of the role of local governments and high expectancy for local governments in the postwar reform.

The Local Autonomy Law (Showa 22 - Act 67) was enforced on May 3, 1947 (Syowa era 22). This was the same day as the enforcement of Japanese Constitution. The Local Autonomy Law was enacted as the fundamental law about local autonomy and integrated the "Tokyo To Sei" , "Dou Fu Ken Sei", "Shi Sei", "Chou Son Sei", "Chihoukan Kan Sei", and some others. Because the presidents of Fu and Ken came to not have their local execution body of the central government, the articles about control and supervision of the central government to the agency delegated functions of the mayors of cities, towns, and villages came to apply to the presidents of Fu and Ken.

Article 6 of the Local Autonomy Act enacted that abolishment, creation, division, amalgamation, and alternation of boundaries of prefectures would be established by law. This was same as under the "Fu Ken Sei." Following Article 95 of the Constitution enacting that establishment of local autonomy special law was needed to be voted by the residents, it is interpreted that it is necessary for the enactment of the law to be voted by the residents of the related prefectures.

　

Prefectural system after WW2 can be divided into following 5 phases:

This recommendation also said "Prefecture does not have prior position than city, town, and village. However, as prefecture is located in the position that it includes city, town, and village, prefecture shall accommodate the big imbalance among city, town, and village when prefecture is in the communication between the central government and city, town, and village. The relationship between city, town, and village and prefecture is as same as one between local governments and the central government."

The second recommendation in September 1951 (Showa era 26) stated about the right-sizing of prefectures that "The standard of the population shall be 2 million and the size shall be decided by considering the cultural, economical, and social close relationship among the areas not by considering the past history such as Han. Small prefectures should examine the right-sizing in order to efficiently execute their broader-based administration."

The recommendation also stated about "Do and Shu", the concept for the new units of local authorities that "There are two opinions about Do and Shu. One is to create Do and Shu outside of current prefectures. The other is to create Do and Shu with abolishment of current prefectures. However, this council opposes them because first one will make administrative system more complicated and would increase the administrative expenditure and the second one will not make local autonomy strong."

This recommendation was very comprehensive and very progressive, which was shown in that it mentioned the reconsideration of 1) administrative functions imposed upon local governments by the central government and 1) field agencies of the central government. However, this recommendation was not implemented because of the change of occupation policy and the less motivation of the central government to implement it.

In May 1951 (Showa era 26), Mr. Ridgeway, who became the General of the GHQ after Mr. Macarthur, presented the statement about the relief of the GHQ's occupation policy for the coming Japanese independence at the timing of the fourth year of the new Constitution. He also requested the Japanese government to review several Acts and government ordinances, such as Potsdam government ordinance which were enacted based on the GHQ's directions. He also admitted that the Japanese government itself would modify the asymmetries of the administrative systems based on the occupation policy. The reforms of local autonomy systems, which were conducted in the process of review of the occupation policy beginning at his statement, generally aimed at changing the administrative system to be efficient and cutback.

In August 1952 (Showa era 27), the Act of establishment of Local Government System Research Council (Showa era 27 - Act 310) was enacted to "comprehensively examine the current local autonomy system for realizing the fundamental principles of the Japanese Constitution." Based on this Act, members of the Council were appointed on December 16, 1952 (Showa era 27) and the first general assembly meeting was held on the next day. At the meeting, the Prime Minister consulted the Council "There is necessity to change the current local autonomy system. Please show the points how to change it." On October 16, 1953 (Showa era 31), the first Local Government System Research Council submitted the "verdict about the reform of local autonomy" in the near future. Based on this verdict, in 1956 (Showa era 31), the Local Autonomy Act was revised for the sixth time. One of the main points of this revise was to clarify the difference of position and authority between prefecture and city, town, and village. This revise said that city, town, and village were the nearest government for the residents and should be the "basic local governments" which were responsible for general administrative affairs, while prefectures were between the central government and city, town, and village and were "local governments on broader unit area" to be responsible for following affairs:

This revise was intended to clarify the difference of functions of prefecture and ones of city, town, and village, which had not been clear and to clarify that prefecture and city, town and village should cooperate each other with being responsible for different administrative affairs for the purpose of executing the smooth local administration.