The subject of Japan's police is an interesting one. Japan's boys in blue are organized under the umbrella of the National Police Force, one of the first areas of society to be modernized in the European model when the country began its transformation from a feudal backwater into an industrialized nation in the 1870s. As with the Ministry of Education, Japan's police are a very top-down organization, and there's little variation between police in different parts of the country, from Hokkaido to Okinawa. One reason often given for the lower rate of crime in Japan is the efficient system of Koban, the so-called "Police Boxes" or small police stations situated around Japanese cities. If you have a problem or need to ask for directions, there's usually a Koban nearby where you can get help at, and I think the system works better than large, centralized police stations. Up til now, these small police boxes have been staffed mainly by men, due to fears that female officers might be in danger if they were asked to work night duty. This policy is about to officially end, however, as police boxes in Tokyo start employing female officers at all hours of the day and night.
This koban in Shibuya is rather famous, since there's a "soapland" right behind it -- so much for prostition being illegal.