Don't look now, but some new bad guys have come to town. Referred to as han-gure, they've actually been around for a while already, flying under the radar of the mainstream media.
Atsushi Mizoguchi, an investigative journalist specializing in coverage of organized crime, is credited with having coined the term han-gure shūdan in his 2011 book from Kodansha, "Yakuza Hokai" (the downfall of the yakuza) to describe these loosely organized groups. In most English reportage up to now, they've been referred to as "former members of hot-rod gangs" or "non-designated crime groups."
The han in han-gure means "half"; the gure derives from gureru, a type of reverse slang with roots in the pre-modern era, created by flipping the order of syllables in the word hamaguri (clam) to guri-hama. The verb gureru was then extracted, to mean when the top and bottom halves of the shells of a mollusk are not matched and therefore don't close uniformly, i.e., a misfit.