during the war, japanese criminal organizations (the yakuza and others) were at times treated like privateers, smuggling goods (including prostitutes) in and out of occupied areas. legitimate japanese merchants also participated in this illicit trade in the war years.

but gang tattoos marked draftees in the japanese army for particularly brutal treatment from superior officers, including beatings and deprivation of food and sleep.

the yakuza is traditionally associated in modern japan with far-right nationalist extremism, and yakuza endorsed imperial japan's military expansion, racial violence and authoritarianism. further yakuza enjoyed many ties to some of the most prominent political and military families. before the war, yakuza soldiers were regularly used by the imperial government to crack down on left-wing political groups and labor organization.

but the war years saw many gang members pressed into military service or targeted by the brutal imperial police force, and japan's thriving wartime economy weakened public interest in illicit enterprises like drugs and gambling.

the post-war devastation of japan fueled a rise in all sorts of criminality from black markets to protection rackets (and there was no longer a powerful police force to stop them), making the yakuza far more influential than it had ever been before and leading to a period in the 1950s of mass gang wars.

SOURCES: The Japanese Mafia: Yakuza, Law, and the State By Peter B. E. Hill, Yakuza: Japan's Criminal Underworld By David E. Kaplan, Alec Dubro