Roppongi is a section of Tokyo's Minato ward infamous for its nightlife, much of which is geared squarely at foreigners. But Roppongi has recently become respectable again even among the Japanese thanks to the opening of Roppongi Hills, a massive shopping and dining complex.
The area features numerous bars, nightclubs, restaurants, and other forms of entertainment including hostess clubs and cabarets. Among the Western expatriate community, it tends to be favoured by business people and financial workers as well as off-duty military.
In the past, Roppongi had a reputation as an area with high Yakuza presence, whether as customers at Roppongi establishments, conducting business, or managing or owning clubs and bars in the area. Although still exerting some influence in Roppongi, in recent times they appear to have shifted much of their presence to other districts in the Tokyo area.
Each nightclub caters to its clientele. “Although most of the clubs are open to all races, and Japanese predominate everywhere, the kind of music played depends on the race of the next largest racial group.” The all-Japanese clubs play Asian pop but mix in some black pop as well. Clubs visited by mostly whites play dance music and rock with just a little hip-hop. The night clubs that draw mostly black patrons play hip-hop and reggae. In Japanese clubs there is an even distribution of Japanese men and women. White clubs have a mixture of women from across races; and black clubs are made up of almost all black men and Japanese women.
(reference: Wikipedia, Wikitravel)

.