THE Yamaguchi-Gumi, one of the world's largest and most ferocious gangs, is estimated to earn over $6 billion a year from drugs, protection, loan-sharking, real-estate rackets and even, it is said, Japan’s stock exchange. This year, the organisation's 100th, over 2,000 of its 23,400 members split away, leaving police nervous about what fallout might follow; a war between rival gangs in the mid-1980s claimed over two dozen lives. And yet membership of the yakuza—as Japan'scrime syndicates are known—isnot technically illegal. Finding a mob hangout requires little more than a telephone book. Tokyo’s richest crime group has an office tucked off the back streets of the glitzy Ginza shopping district. A bronze nameplate on the door helpfully identifies the Sumiyoshi-kai, another large criminal organisation. Full gang members carry business cards and register with the police. Some have pension plans. The yakuza emerged from misfit pedlars and gamblers in the Edo period (between 1603 and 1868) that formed into criminal gangs. During Japan’s turbo-charged modernisation, they reached deep into the economy; after the second world war they grew powerful in black markets. Their might peaked in the 1960s with an estimated membership of 184,000. At their zenith, they had strong links to conservative politicians and were used by the Liberal Democratic Party (LDP), Japan’s post-war political behemoth, to break up unions and left-wing demonstrations. Such ties may not have completely faded.

This history may explain in part why the gangs are not exactly illegal. But partly under pressure from America, which wants Japan to rein in financial crime, the mob is being brought to heel. Yakuza-exclusion ordinances, introduced three years ago, stop companies from knowingly engaging in business with gangsters. Businesses from banks to corner shops are now obliged to confirm that customers have no ties to organised crime. Known gangsters cannot open bank accounts. Still, there are no plans to criminalise the gangs themselves. The police believe that would drive crime underground, says Hiroki Allen, a security and finance consultant who studies the yakuza. At least now they are regulated and subject to the law, he says: gangsters have often been known to surrender by walking into police stations. “If one member does something bad you can call in the boss and take the whole gang down,” he says.

The upshot is that the yakuza still operate in plain view in a way that would be unthinkable in America or Europe. Fan magazines, comic books and movies glamorise them. Major gang bosses are quasi-celebrities. Though membership has shrunk to a record low of 53,500, according to the National Police Agency, "muscle work" is subcontracted to freelancers with no police records. A tougher core of gangsters has migrated from the mob's traditional cash cows into financial crimes that may be harder to detect. The yakuza have also been involved in the Fukushima nuclear cleanup and are thought to be eyeing rich pickings from construction and entertainment ahead of the 2020 Tokyo Olympics. As long as violence from the recent split does not spill over into the streets, nobody expects the yakuza to be seriously impeded. Japan, it seems, prefers organised crime to the disorganised alternative.

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Japan's criminal gangs are experiencing a rare break-up (September 2015)