Either you erase the story, or we’ll erase you. And maybe your family. But we’ll do them first, so you learn your lesson before you die." The speaker used certain ambiguous phrases—Japanese is apparently a wonderful language for crooks because its personal pronoun system allows you to implicitly threaten a person even while the casual listener might not hear anything more incriminating than “or something else may be erased". But Jake Adelstein, who is originally from Missouri, US, had studied at a Tokyo university and worked as a crime reporter for a Japanese newspaper. So the subtle meaning of “something else" was very clear to him.

I caught up with Adelstein on a book tour in Australia, where he was launching his debut Tokyo Vice—billed as “a unique, first-hand, revelatory look at the underbelly of Japanese culture". I had to reschedule the interview thrice: Each time he had already moved on to the next town—usually leaving behind demolished hotel breakfasts looking like origami artwork made of discarded bread slices. By the time I finally cornered him at a book signing, I’d begun to understand how he’d survived 12 years in an 80-hours-a-week job in Japan: Adelstein is obviously one of the fastest and smartest Americans around.

When he graduated in Tokyo in 1992, he saw an ad and thought it might be fun to test his skills by doing the standardized entrance test that Japanese newspapers put prospective new staff members through. Nobody had ever heard of a foreigner passing it, so Adelstein—who, on one level, seems to be quite the quixotic type—simply had to try.

Other world: Jake Adelstein was a crime reporter for a newspaper.

Suddenly, he was working for one of the world’s biggest (over 10 million copies sold daily) and most sensational newspapers, Yomiuri Shimbun, filing reports about criminals who ran pet shops and ground down murder victims to feed the mince to dogs. As a teenager, he was hooked on Raymond Chandler, Dashiell Hammett, Ross McDonald, Lawrence Block and other great American pulp crime writers, and covering the police beat was perhaps like living out some such noir teenage fantasies.

It is quite clear that Adelstein knows the Yakuza inside out—Japanese gangs, the last remnant of the feudal Japan, infused with tough samurai-like traditions, who employ tens of thousands of full-time gangsters to make money on anything from drugs, extortion and gambling to human trafficking and even murder. Officially known as “designated violent groups", they operate in a very business-like manner in their Armani suits and corporate offices (which makes them different from other crime syndicates, such as the mafia that still tries to remain a secret society). To some people, they are like heroes; there are even Yakuza fan magazines, graphically illustrated and popular among ordinary men who’d like to imagine lives different from their stifling day-to-day existence.

Within this crooked world, Adelstein stayed alive by figuring out the snakes and ladders, and he learnt the tricky art of how to conduct oneself while meeting dangerous criminals. Gangs sometimes inform on each other to gain corporate advantage, so a journalist can be useful for the Yakuza. Also, a journalist may have information to share in order to get information, so promoting good public relations seems to be part of the Yakuza strategy.

But the Yakuza use Google Alerts to track what is being written about them and they can get quite unhappy if the coverage doesn’t suit their self-image. Adelstein started receiving thinly veiled death threats from tattooed men missing a pinkie—another Yakuza membership sign. It isn’t often that a writer gets such explicit feedback, I think to myself, but then again Adelstein made it his business to stir up storms. His great scoop was exposing how the bosses—whose livers frequently died on them because of their hugely unhealthy body tattoos—went to the US and bought themselves liver transplants via shady deals.

After that things started to develop in a dangerous direction. While working on his book Tokyo Vice, Adelstein got into semi-mortal combat with one particularly crooked crook. In order to get out of the situation, Adelstein punched the crook in the larynx, to choke him, but the crook just kept attacking until Adelstein finally pulped his knee caps with a golf club. Afterwards he borrowed the man’s cellphone and dialled for an ambulance.

These days Adelstein suffers from post-traumatic stress disorder, and tells me that he has a personal bodyguard: an ex-Yakuza loan shark who ensures that he won’t “be erased". Despite glowing reviews—“crisp storytelling and an unexpectedly earnest eagerness to try to rescue the damned" wrote Pico Iyer in Time—his Tokyo Vice can never be published in Japan. Or Adelstein might find himself buried alive in the concrete foundations of a Tokyo amusement park, the publishing house could be torched, and its employees kidnapped by gangsters. But, curiously, the book also works as a kind of life insurance—if the Yakuza bump him off, it would prove to the world that everything in it is true.

And that is something the Yakuza, hopefully, will prefer to live without.

Zac O’Yeah is a Bangalore-based writer of crime fiction whose last published novel is Once Upon a Time in Scandinavistan.

Write to Zac at criminalmind@livemint.com