Prefectural police

In the law enforcement system in Japan, prefectural police are prefecture-level law enforcement agencies responsible for policing, law enforcement, and public security within their respective prefectures of Japan. Although prefectural police are, in principle, regarded as municipal police, they are mostly under the central oversight and control of the National Police Agency.
As of 2020, the total strength of the prefectural police is approximately 260,000 sworn officers and 28,400 civilian staff, a total of 288,400 employees.

History

In the Empire of Japan, territorial police forces were organised as departments of police of each prefectural offices. They were placed under complete centralized control, with the Police Affairs Bureau of the Home Ministry at their core.
After the surrender of Japan, the Supreme Commander for the Allied Powers regarded this centralized police system as undemocratic. During the occupation of Japan, the principle of decentralisation was introduced by the 1947 Police Law. Cities and large towns had their own municipal police services, and the National Rural Police was responsible for smaller towns, villages and rural areas. However, most Japanese municipalities were too small to have an effectively large police force, so sometimes they were unable to deal with large-scale violence. In addition, excessive fragmentation of the police organisation reduced the efficiency of police activities.
As a response to these problems, complete restructuring created a more centralized system under the 1954 amended Police Law. All operational units except for the Imperial Guard were reorganized into the prefectural police departments for each prefecture and the National Police Agency was established as the central coordinating agency for these police departments.

Organisation

Each prefectural police department comprises a police authority and operational units: Prefectural Public Safety Commissions and Prefectural Police Headquarters.

Prefectural Public Safety Commission

Prefectural Public Safety Commissions are administrative committees established under the jurisdiction of prefectural governors to provide citizen oversight for police activities. A committee consists of three members in an ordinary prefecture and five members in urban prefectures. The members of prefectural public safety commission are appointed by the governor with the consent of the prefectural assembly.

Prefectural Police Headquarters

In Tokyo, the Prefectural Police Headquarters specifically refers to the Tokyo Metropolitan Police Department. Also, Hokkaido Prefectural Police Headquarters is known as, and those in Ōsaka and Kyoto Prefectures are known as, and are distinguished from other Prefectural Police Headquarters.
The Chiefs of Prefectural police headquarters are appointed officials at the top of the chain of command in each Prefectural Police Headquarters. In the Tokyo Metropolitan Police Department, the name of Superintendent General is used.
These police departments are responsible for every police actions within their jurisdiction in principle, but most important activities are regulated by the National Police Agency. Police officers whose rank are higher than Assistant commissioner #Japan are salaried by the national budget even if they belong to local police departments. Designation and dismissal of these high-ranking officers are delegated to the National Public Safety Commission.
Each Prefectural police headquarters contains administrative departments corresponding to those of the bureaus of the National Police Agency as follows:

Police administration department
Criminal investigation department
Traffic department
Security department
Community safety department

In addition, urban prefectural police departments comprise a general affairs department and a community police department.
There are some 289,000 police officers nationwide, about 97% of whom were affiliated with Prefectural Police Headquarters.

Community policing

In the Japanese police, community policing is treated as being close to crime prevention, and in rural prefectural police, community safety departments in charge of crime prevention sometimes concurrently handle community policing. Community policing officers are organised into several police stations. Each station includes the following sections:

Police administration section
Traffic section
Security section
Community police affairs section
Community safety section
Criminal investigation section

Officers of the community police affairs sections are distributed in their jurisdictions, working at police boxes, residential police boxes, radio mobile patrols, etc.
These community policing officers are supported by the community police department or the community safety department of the prefectural police headquarters. In addition to the administration of the police radio networks, they provide inter-regional patrol units and air support: automobile patrols and a police aviation unit, and many other assets.

Traffic policing

Originally traffic policing was mainly done by community policing officers. However, with the progress of motorization since the 1950s, traffic accidents have increased dramatically, resulting in the so-called traffic war, the system of traffic police was also strengthened.
From the mid-1960s, mobile patrol units were installed at several PPHs, and in 1972 they were installed at all traffic departments of the PPHs as Mobile Traffic Units. Traffic cars and police motorcycles are deployed in these units. And as the development of the expressway advanced, the establishment of the Highway patrol#Japan was also decided in 1971.

Criminal investigation

In the Empire of Japan, the criminal investigation was presided over by prosecutors, like the ministère public does in French law. With the 1947 Police Law and the 1948 Code of Criminal Procedure, the responsibility of investigation has been defined to be uniquely assigned to police officers. In order to fulfil this responsibility, criminal investigation departments or criminal investigation bureaus were set up in each police organisation. After the establishment of the 1954 amended Police Law, these departments are supervised by the Criminal Affairs Bureau of the National Police Agency.
Criminal investigation departments or criminal investigation bureaus maintain two investigation divisions, an organised crime investigation division, a mobile investigation unit, and an identification division. The mobile investigation units are first responders for initial criminal investigations, distributed among the region with unmarked cars. The Special Investigation Team are specialised detective units of the first investigation divisions, well acquainted with new technology and special tactics including tactical capabilities. They are mandated for critical incidents except for terrorism, but in some rural but well-versed prefectural police like Aomori Prefectural Police, these detectives can form a counterterrorism task force together with uniformed officers and riot specialists.

Public security

In the Tokyo Metropolitan Police Department, the jurisdiction for public security policing is divided into the Tokyo Metropolitan Police Department Public Security Bureau and Security Bureau, being responsible for investigation activities and security forces operations, respectively. In other PPHs, their security departments are in charge of all public security policing matters; but in the departments, they are divided in the same way as they are done by the MPD. They are supervised by the Security Bureau of the National Police Agency.
Within their security departments or bureaus, each PPH maintains Riot Police Units, which serve as a rapid reaction force capable of fulfilling riot police, police tactical unit, and search and rescue roles. Full-time riot police can also be augmented by regular police trained in riot duties.
Counterterrorism operations are also the affairs of the security departments. The Special Assault Teams are the national-level units and Riot Police Unit#Specialist squads are the local units. These units are established within the RPU basically, but the SAT of the TMPD and Osaka PPH are under direct control of their Security Bureau or Department.

Ranks

Police officers are divided into nine ranks:

Status	Police ranks	Comparable military ranks	Representative job title	Rank insignia	Shoulder Cords
	Commissioner General	No counterpart	The chief of the NPA
	Superintendent General	General	The chief of the TMPD
	Senior commissioner	Lieutenant general	Deputy commissioner general, deputy superintendent general, the chief of a regional police bureau and the chief of a PPH
	Police commissioner	Major general	The chief of a PPH
	Assistant Commissioner	Colonel	The chief of a police station
Local police personnel	Superintendent	Lieutenant colonel	The chief of a small or middle police station, the vice commanding officer of a police station and commander of a riot police unit
Local police personnel	Chief inspector	Major or captain	Squad commander in a police station and leader of a riot company
Local police personnel	Inspector	Captain or lieutenant	Squad sub-commander in a police station and leader of a riot platoon
Local police personnel	Police sergeant	Warrant officer or Sergeant	Field supervisor and leader of a police box
Local police personnel	Senior police officer	Private first class	Honorary rank of police officers
Local police personnel	Police officer	Private	A prefectural police officer's career starts from this rank

The National Police Agency Commissioner General holds the highest position of the Japanese police. His title is not a rank, but rather denotes his position as head of the NPA. On the other hand, the Tokyo Metropolitan Police Department Superintendent General represents not only the highest rank in the system but also assignment as head of the TMPD.