Gonin Gumi
The gonin gumi (五人組み) were groups of five households that were held collectively responsible, in a manner similar to the frith-borh in England, during the Tokugawa period of Japanese history. All households in the shogunate were members of such a group, with all members of the group held responsible for the good conduct of all of the other members, and of their dependents. The responsibility included responsibility for crime and for non-payment of taxes.[1][2]
The gonin gumi were primarily aimed at combating the vagabondage and brigandage of the time, including mutual defence against the ronin. They were headed by a leader who was usually elected from within, but sometimes appointed from above. The groups did not always contain five households. In some districts, the groups could comprise six, or even ten, households.[1]
The gonin gumi are sometimes erroneously conflated with the ryo-donari (a.k.a. muko-sangen), which are informal social institutions. The gonin gumi were formal institutions, involved in law enforcement.[1]