Readers living or traveling in Japan’s capital may note that Tokyo police officers and patrol cars bear the characters 警視庁, or keishichou. At first glance it appears to be the characters for the National Police Agency (NPA), except the middle of the three characters is different — the NPA is 警察庁, or keisatsuchou. Keishichou is the unique name attributed to the Tokyo Metropolitan Police Department. For a Japanese speaker even mildly familiar with the structure of government in Japan, this looks peculiar — why is a prefectural police department named in such a way that it appears to be a national agency?
The history begins with the Meiji Restoration, when the keishichou was established in 1874 to protect and police the seat of government. As a police department, it had a unique role from the time of its establishment — some of its officers were organized into a division that fought for the Imperial government in the Satsuma Rebellion. The keishichou at this time served as a prefectural police department, but it was an agency of the government, subordinate to the cabinet, and Tokyo prefecture only had the authority to decide its budget. Later, the department also housed the Tokko special police force, the civilian counterpart to the military’s Kempeitai, taking part in both criminal investigation and counter-espionage functions.
The headquarters of the keishichou was situated just outside Sakuradamon, the southern gate of Edo Castle/Imperial Palace, possibly due to its importance in guarding the emperor, but also because that site was the location of an infamous assassination a decade earlier, and the location of the agency may have been a show of authority. The jolly Victorian structure was unfortunately destroyed in the 1923 Great Kanto Earthquake, as witnessed below. (Today, the Keishichou is right next to Sakuradamon gate, and the NPA is in the building next to it.)
During the Occupation, the Keishichou was reformulated under the old police law, and added the imperial police under its jurisdiction, which had previously been a wholly independent branch of authority. During the same time, GHQ set up a similar keishichou in Osaka, which only lasted for the years of the Occupation.
After the Occupation, Tokyo’s Keishichou became an ordinary prefectural police department, but kept its name and retained some of its unique functions. From a jurisdictional standpoint, most prefectures are divided into wards with different departments of the prefectural police having jurisdiction over certain regions of each prefecture. Only Tokyo and Hokkaido have police departments where one department and all of its officers have responsibility for the entire prefecture, without divisions into areas. Also, the keishichou maintains some additional responsiblities, being responsible also for policing the Imperial Family, the Diet, the administrative agencies, the cabinet, the embassies of foreign nations in Japan, and other important people (officers of the keishichou were dispatched to Hokkaido for the G8 summit). The Keishichou is also the only prefectural police department that handles any fire truck activities (typically a separate task handled by the shoubouchou, or Fire Prevention Agency) because the imperial police force have this task especially assigned to them as part of their duties.
Interestingly enough, metropolitan police departments that provide similar functions in other countries, such as Scotland Yard in London and the Paris Prefecture Police are often translated as keishichou as well.