The idea that merger of towns and villages was necessary has been supported by not only national government, but also by the persons concerned such as mayors, local assembly members, officers, and residents in the process of strengthen local autonomy, in particular the role of municipalities after World War Second. And it has been considered that the removal of various systematic obstacles to merger and in addition the more positive supports for it were essential in order to actually promote merger of towns and villages.

In this context, as the results of the supports given by all ministries and agencies, mainly by the Agency of Home Affairs, and cooperation between the authority of towns and villages such as the Nation-Wide Group of Towns and Villages, the Diet, and each political party, "Merger of Towns and Villages Promotion Law" was enacted as a law initiated by Representatives, and enforced as a time-limited law for 3 years on October 1, 1953.

Article 3 Section 1 of Merger of Towns and Villages Promotion Law said, "The standard towns and villages have population of more than about 8,000". According to this provision, "Basic Plan for Promoting Merger of Towns and Villages" approved by Cabinet on October 30 1953 provided that the number of municipalities after the merger plan would be 3,373 in a way that 1,500 towns or villages among the 95 percent of 8,245 towns and villages (that is, 7,832) which had population less than 8,000 should be merged into the towns or villages which had population 8,000 or more, and the remaining 6,332 towns and villages should merge by every 4 towns or villages on average by the end of September 1956, which was the time limit of the Law.

This Plan also demanded that the investigation into the actual circumstances be done during 1953, that Council for Promoting Merger of Towns and Villages be established by November 1 1953, and that the plans for merger of towns and villages of each prefecture be made by March 1954 in order to achieve 80 percent of the aim by the end of April 1955 (when the elections of local assembly members and mayors were held in most towns and villages). It is understandable that each prefecture made considerable efforts to realize the merger of towns and villages with the help of various administrative and financial measures mentioned below.

The various administrative and financial measures provided by Merger of Towns and Villages Promotion Law included not only those for removing obstacles to merger but also those for positively promoting merger of towns and villages. The major examples of specific measures for removing obstacles to merger were "exceptional measures for the term and number of local assembly members", which assured the positions of local assembly members of towns and villages for a certain period after merger, and "exceptional measures for the Equalization Grant Law", which assured the total amount of equalization grant of related merged towns and villages for the fiscal year when they merged and the following 5 years. On the other hand, measures for positively promoting merger of towns and villages included "subsidies for promoting merger of towns and villages" and "measures taken by national government and prefectures for executing plans to construct new towns and villages".

These administrative and financial measures were considered as great help for towns and villages in those days which recognized the necessity of merger of towns and villages, and which faced with the increasing amount of affairs such as the establishment and administration of new middle school system under the fiscal crises. As the result of considerable efforts made by persons concerned in municipalities and prefectures, the number of municipalities decreased from 9,868 even to 3,975 for 3 years of enforcement of Merger of Towns and Villages Promotion Law.

Other than these factors, "the movement of becoming city" and large-scale enlightenment projects which were epoch-making in those days were also the factors of promoting merger of towns and villages.

The number of population in order to become city increased from over 30,000 as of the enforcement of Local Autonomy Law to over 50,000 since September 20 1954 according to the amendment of the Law according to the Second Recommendation made by Committee for Investigating Local Administration (September, 1951) and the report made by Council for Investigating Local System (October, 1953). But the merger of towns and villages in order to become city before the change of the requirement produced promoting powers for the early merger rush of the Showa era, which was also called "the movement of becoming city".

As for the enlightenment projects, "Execution Plan for Publicity and Advertisement of Merger of Towns and Villages" was approved by Cabinet in December 1953, which provided that the subjects related to merger of towns and villages should be dealt with in nation-wide events (this was realized as "General Exhibition of Local Autonomy" which aimed at commemorating mergers of towns and villages and at introducing new cities at Mitsukoshi in Nipponbashi, Tokyo in fall 1954) and radio drama programs in addition to pamphlets and posters in Tokyo, that public papers, exhibitions, movies and so on should be utilized in prefectures, and that meetings and community centers should be utilized and in addition the subjects should be considered as a project theme of social studies and so on in education in towns and villages.

Before Merger of Towns and Villages Promotion Law expired, "New Municipalities Construction Promotion Law" was enacted and enforced on June 30 1956 in order to soundly raise and develop the new municipalities through merger, and to promote mergers among towns and villages which had not merged yet. It was true that New Municipalities Construction Plan basically took over New Towns and Villages Construction Plan based on the previous law. But it had the characteristics as a general management plan of related municipalities based on concreteness and generality according to regional characteristics, and on reality and effectiveness according to the fiscal conditions of related municipalities. This spirit has been taken over by "Basic Framework of Municipalities" provided by Article 2 Section 5 (Article 4 currently) of Local Autonomy Law thereafter.

As for the merges among the towns and villages which had not merged yet, New Municipalities Construction Promotion Law provided provisions such as more recommendations made by governors of prefectures and referenda in order to achieve these merges as much as possible. As a result, the number of municipalities decreased to 3,472 when the Law partly expired (June 1961).

In the former half of 1960's, the movement of the merges among cities such as the merge among 5 cities in the northern part of Kyushu became active instead of the mergers among small towns and villages. "Law for Exceptional Measures on City Merger" which was applied to the cases of new mergers among 3 or more cities or between 2 or more cities and 1 or more towns and villages was enacted, which provided the exceptional measures such as those related to the term of local assembly members of related municipalities and those related to electoral districts of the House of Representatives. In addition, "New Industrial City Construction Promotion Law" which aimed at constructing cities which were expected to become the cores of the development of the developing area in that area, and "Industrial Development Special District Development Promotion Law", which aimed at promoting the development of special districts for industrial development which were expected to become the cores of regional development, also provided not only the provision that related municipalities should consider their appropriate scales through municipal merger but also exceptional measures related to the term of local assembly members under merger and so on.