, or Japanese mafia are not allowed to show their tattoos in public except during the Sanja Matsuri
In today's usage, the term "gang" is generally used for a criminal organization, and the term "gangster" invariably describes a criminal. Much has been written on the subject of gangs, although there is no clear consensus about what constitutes a gang or what situations lead to gang formation and evolution. There is agreement that the members of a gang have a sense of common identity and belonging, and this is typically reinforced through shared activities and through visual identifications such as special clothing, tattoos or rings. Some preconceptions may be false. For example, the common view that illegal drug distribution in the United States is largely controlled by gangs has been questioned.
A gang may be a relatively small group of people who cooperate in criminal acts, as with the Jesse James gang, which ended with the leader's death in 1882. But a gang may be a larger group with a formal organization that survives the death of its leader. The Chicago Outfit created by Al Capone outlasted its founder's imprisonment and death, and survived into the 21st century. Large and well structured gangs such as the Mafia, drug cartels, Triads or even outlaw motorcycle gangs can undertake complex transactions that would be far beyond the capability of one individual, and can provide services such as dispute arbitration and contract enforcement that parallel those of a legitimate government.
The term "organized crime" is associated with gangs and gangsters, but is not synonymous. A small street gang that engages in sporadic low-level crime would not be seen as "organized". An organization that coordinates gangs in different countries involved in the international trade in drugs or prostitutes may not be considered a "gang".
Although gangs and gangsters have existed in many countries and at many times in the past, they have played more prominent roles during times of weakened social order or when governments have attempted to suppress access to goods or services for which there is a high demand.