I meet Kohei Oka on a Tokyo street in front of a high-end jewelry store that was recently robbed in broad daylight by a gang of Colombian thieves. Oka-san is a middle-aged man of considerable girth and surprisingly delicate movements. It is raining outside, and he holds a golf umbrella aloft between his thumb and first two fingers, as if it were as light as a flower. It is illegal for yakuza to have business cards, he tells me when I hand him mine. As the exchange of such cards, or meishi, is one of the most sacred and inviolable rituals of Japanese public life, the crackdown is intended to make it difficult for the yakuza—Japan's notorious organized crime families—to do business.

"I am glad that you understand the brute unfairness of this law," Oka-san says, slipping me his meishi, which identifies him as the general secretary of the Kobayashi-kai, one of Tokyo's biggest and richest yakuza families, with fashionable addresses in Ginza and Roppongi.

Otherwise known as the Ginza police, the Kobayashi-kai are the best-dressed gangsters in Japan and perhaps anywhere else in the world, a gang of stylish racketeers who keep Tokyo's famous high-end shopping and nightlife district safe—for a price, of course. In addition to their mastery of the arts of extortion, protection, and kickbacks, the Kobayashi-kai can justly claim to have inspired movie directors from the New Wave god Jean-Pierre Melville to the Japanese auteurs Seijun Suzuki and Kinji Fukasaku to Quentin Tarantino with their bizarre rituals, outcast style, and distinctive tailoring.

As it happens, my friend Velisarios Kattoulas, familiarly known as Veli, is a crack reporter in Tokyo who has gained the confidence of leading members of the Kobayashi-kai. After taking Veli to an expensive lunch one afternoon at L'Atelier de Joël Robuchon, I mention that while I have never been a fan of full-body tattoos or having my fingers amputated at the first knuckle, I am always in the market for a good suit. Veli agrees to make a few calls, and we arrive at a deal: I will leave the name of the Kobayashi boss of bosses out of my article, in exchange for which favor I will be rewarded with an introduction to Oka-san, a Kobayashi underboss, who will then introduce me to the boss's personal tailor, Sajuuro Watanabe of Watanabe and Sons. If all goes well, and I can come up with the equivalent of $3,000 or so in ready yen, I will obtain a custom-made version of the suit made famous by the chieftain of Tokyo's most stylish criminal gang.