History & Development
Neighborhood mutual-aid associations existed in Japan since before the Edo period. The system was formalized on 11 September 1940 by order of the Home Ministry (Japan) under the cabinet of Prime Minister Fumimaro Konoye. Participation was mandatory. Each unit was responsible for allocating rationed goods, distributing government bonds, fire fighting, public health, and civil defense. Each unit was also responsible for assisting the National Spiritual Mobilization Movement, by distribution of government propaganda, and organizing participation in patriotic rallies. 
The government also found the tonarigumi useful for the maintenance of public security. A network of informants was established linking every neighborhood association with the Tokkō Police to watch for possible infractions of national laws, and suspect political or immoral behavior. 
Tonarigumi were also organized in territories occupied by Japan, including Manchukuo, Mengjiang, and the Wang Jingwei Government, and later in occupied territories of Southeast Asia, with the same purposes.
Later in the Pacific War, the tonarigumi received basic military training to serve as observers for enemy planes over cities or suspicious boats on the coasts. In the final stages of war, it was intended that the tonarigumi form a secondary militia, in the case of enemy invasion. Some tonarigumi took part in combat in Manchukuo, northern Chōsen and Karafuto, in the closing days of the Pacific War.
Formally abolished in 1947 by the American occupation authorities, the system survives to a certain extent in the modern chonaikai, or jichikai which are nominally independent voluntary associations, but which retain a quasi-governmental status in that they have limited responsibility for local administration and coordination of activities such as neighborhood watch and disaster relief.