Even one member of the Japanese Parliament, Kazumi Ota, was a hostess. That revelation once would have ignited a huge scandal, but it has not. She will run for re-election on the leading opposition party ticket, the Democratic Party of Japan, in the national election next month, and the ticket is expected to unseat the ruling party.

It is unclear how many hostesses work in Japan. In Tokyo alone, about 13,000 establishments offer late-night entertainment by hostesses (and some male hosts), including members-only clubs frequented by politicians and company executives, as well as cheaper cabaret clubs.

Hostesses tend to drinks, offer attentive conversation and accompany men on dates off premises, but do not generally have sex for money. (Men who seek that can go to prostitutes, though prostitution is illegal.)

Hostesses are often ranked according to popularity among clients, with the No. 1 of each club assuming the status of a star.

Mineri Hayashi has made it to the top of her club, Celux, six years after coming to Tokyo from northern Japan. One recent evening, she readied herself for an elaborate birthday event her club was throwing in her honor.

Outside the club, bigger-than-life posters of Ms. Hayashi adorned the street. At the club, a dozen men put up balloons and lined up Champagne bottles.

The club’s clientele is diverse, including workaday salarymen, business owners and other men unwinding after work.