They're members of the biggest, meanest organised crime group in Japan, but these tattooed gangsters are being sent back to school by their godfathers.
Under new laws, mob bosses can be sued for the misdeeds of their underlings. So the leaders of the feared Yamaguchi-gumi have begun testing their mobsters' knowledge of the laws.
They've drawn up a 12-page test paper which questions them on a range of banned activities, from bootlegging fuel to dumping industrial waste.
For decades, the Yakuza has been the violent underbelly of Japanese society. Tattooed toughs and punks without pinkies, celebrated and denigrated alike in movies, books and comics.
But these mobsters are feeling the pinch. For a start, the global economic downturn been bad for business and now tough new anti-mob laws are also squeezing these enterprising gangsters.
For example, Yakuza dons can now be sued for crimes committed by their subordinates, meaning they can be cleaned out if their underlings mess up.
Masahiro Tamura is a former chief of the Fukuoka Prefectural Police, a veteran yakuza hunter who commanded a force of 12,000 officers.
"I think this is a good move, because it puts the responsibility on the crime bosses to control their gangsters. It means innocent people are less likely to be targeted," he said.
The crime bosses are looking for ways to beat the news laws so they can save their own skins. And to do that, they've sent their mobsters back to the classroom.
During a raid in central Japan this week, police found a 12-page test paper for yakuza members.
One question asks, "What kind of activities are banned?" And the correct answer: Dumping industrial waste, phone fraud scams, bootlegging fuel and theft of construction equipment.
Former police chief Masahiro Tamura says the Yakuza are merely evolving to suit the new environment.
"I am not surprised at all that the Yakuza are studying the law. The last thing they want is to be fined large amounts or have costs awarded against them in court," he said.
And the godfathers of Japanese crime believe they've already found a few legal loopholes in the new laws.
This was one briefing note recently distributed to Yakuza members of one group:
"It is now illegal to give financial rewards or promote someone who was involved in a hit against a member of a rival gang. But it is not illegal to give them a salary through a front company and promote them within that organisation."
So there you have it: Some free legal advice from Japan's mafia bosses: Don't pay the hit man directly, instead give him a job in a front company and a salary.
So from busting heads on the street to cramming heads for exams, life has never been so cerebral for Japan's Yakuza hard men.