[4] As of 2017, the NPA has a strength of approximately 7,800 personnel: 2,100 sworn officers, 900 guards, and 4,800 civilian staff.

But after the surrender of Japan, the Supreme Commander for the Allied Powers regarded this centralized police system as undemocratic.

Cities and large towns had their own municipal police services (自治体警察, Jichitai Keisatsu), and the National Rural Police [ja] (国家地方警察, Kokka Chihō Keisatsu) was responsible for smaller towns, villages and rural areas.

But most Japanese municipalities were too small to have a large police force, so sometimes they were unable to deal with large-scale violence.

[6] As a response to these problems, complete restructuring created a more centralized system under the 1954 amended Police Law.

[6] The Community Safety Bureau (生活安全局, Seikatsu Anzen-kyoku) is responsible for crime prevention, combating juvenile delinquency, and pollution control.

[12] The Cyber Affairs bureau (サイバー警察局, Saibā keisatsu-kyoku) is in charge of policing in cyberspace, combat with cybercrime and cyberterrorism.