When most of the occupation forces were transferred to Korea in 1950–51 with the Korean War, the 75,000 strong National Police Reserve (predecessor of the Japan Ground Self-Defense Force) was formed outside the Regular police organizations to back up the ordinary police during civil disturbances. And pressure mounted for a centralized system more compatible with Japanese political preferences. The 1947 Police Law was amended in 1951 to allow the municipal police of smaller communities to merge with the National Rural Police. Most chose this arrangement, and by 1954 only about 400 cities, towns, and villages still had their own police forces. Under the 1954 amended Police Law, a final restructuring created an even more centralized system in which local forces were organized by prefectures under a National Police Agency.