The  of the Empire of Japan comprised numerous police services, in many cases with overlapping jurisdictions.

History and background
During the Tokugawa bakufu (1603–1867), police functions in Japan operated through appointed town magistrates of samurai status, who served simultaneously as  chiefs of police, prosecutors and judges. These magistrates were assisted by a professional police-force led by officers who were also of samurai status. In turn, the samurai officers were assisted by deputized commoners known as jittemochi, who were granted  powers of arrest. The citizenry was organized into  goningumi (Five-family associations), the forerunner of the tonarigumi, whose members had collective responsibility for the actions and activities of each one of their fellows. The official formula used in feudal times to inform a subject that he had been placed under arrest was to simply shout "Go'yō!" (御用) – the expression also meant "Official business!" or "Clear the way!".

As part of the modernization of Japan after the 1868 Meiji Restoration, the new Meiji government sent Kawaji Toshiyoshi on a tour of Europe in 1872 to study various law-enforcement systems. He returned impressed with the structure and techniques of the police forces of France's Third Republic and of Prussia as models for the new Japanese police system.  With the establishment of the Home Ministry in 1873, his recommendations were implemented, and civilian police powers became centralized at the national level, although implementation was delegated to the  prefectural level.

Under the Home Ministry, the  also had quasi-judicial functions, including the power to issue ordinances and to regulate business licenses, construction permits, industrial safety and  public-health issues, in addition to its  criminal-investigation and public-order functions. The centralized police system steadily acquired extra functions, until it controlled almost all aspects of daily life, including fire prevention and the mediation of labor disputes.

During the Satsuma Rebellion of 1877, the lack of an organized, trained standing army forced the central government to use units from the police bureau as militia to suppress the uprising.

After 1911, a separate department, the Special Higher Police (Tokko), was established specifically to deal with political crimes and counter-espionage. Similar to Special Branches in the later Commonwealth of Nations, the Tokko investigated and suppressed potentially subversive ideologies, including anarchism, communism, and socialism, as well as monitoring the growing foreign population within Japan. Its scope gradually increased to include religious groups,  pacifists, student activists, liberals, and ultra-rightists. The Tokko also regulated the content of motion pictures, political meetings, and election campaigns. 

The military came under the police jurisdiction of the Kempeitai (founded in 1881) for the Imperial Japanese Army and the  Tokkeitai (founded in 1942)
for the Imperial Japanese Navy, although both military organizations had overlapping jurisdiction over the civilian population.

In the Shanghai International Settlement the Japanese Consular Police was established and kept under the control of the Japanese consulate in order to apprehend Japanese wanted for crimes committed against the state.

After the Manchurian Incident of 1931, military police assumed greater authority, leading to friction with their civilian counterparts. After the start of the Second Sino-Japanese War in 1937, police regulated industry and commerce (to maximize the war effort and to prevent speculation and hoarding), mobilized labor, and controlled transportation.

Japan set up civil police services overseas (in  Korea, Kwantung Leased Territory,  Taiwan, Karafuto, some extraterritorial Japanese dependencies in Shanghai, Peking and  Tientsin before war started on the  Chinese mainland). From the 1930s period to the Pacific War of 1941-1945, other similar but "native" civil police-services operated in Manchukuo, Mengjiang and the  Nanking Nationalist Government. The police and security services in the South Seas Mandate and occupied Pacific areas were the charge of the Tokeitai.

The Tokyo metropolitan area came under the jurisdiction of the Teikoku Keishichō (帝國警視廳) or Keishichō, which was personally headed by Kawaji from 1874, and from which he could direct the organization of the national police system.

The vague wording of the 1925 Peace Preservation Law gave all police organizations wide scope for interpretation of what constituted "criminal activity", and under the guise of "maintenance of order", the police exercised broad powers of surveillance and arrest. Lack of accountability and a tradition of "guilty until proven innocent" led to many of the brutalities carried out by the police forces. In rural areas especially, the police had great authority and were accorded the same mixture of fear and respect as the village head. The increasing involvement of the police in political affairs was one of the foundations of the authoritarian state in Japan in the first half of the twentieth century.

After  Japan surrendered in 1945, the  American occupation authorities retained the prewar police structure pending the implementation of a new system. The Diet of Japan passed the 1947 Police Law to set up new decentralized systems:  and the . But this system didn't match the Japanese national situation, so a complete restructuring ushered in a more centralized system with the National Police Agency and prefectural police departments under the 1954 amended Police Law.

Service weapons 
At the beginning of modern police systems, only senior officers were permitted to wear a sword, so most constables had only a baton. Then, in 1882, all officers started to be issued a sabre.

Only some elite detectives, bodyguards, or SWAT units such as the Special Security Unit of the TMPD were issued pistols. FN Model 1910 or Colt Model 1903 were used for open-carry uses, and FN M1905 or Colt Model 1908 Vest Pocket for concealed carry uses. And in the border area like Karafuto Prefecture and Korea, there were some armed police units with military small arms.

See also
Kempeitai
Tokeitai
Tokko
Tokyo Metropolitan Police Department
Law enforcement in Japan
National Police Agency

References

External links

Politics of the Empire of Japan
Law enforcement in Japan