The most disturbing single fact that I learnt from BBC2's documentary Geiko Girl (Sunday 20 August, 9pm) was that the Shinto god of women doubles as the god of entertainment. If that does not sum up old Japan's take on women, I don't know what would. But Mick Csaky's oddly uninflected documentary, the last in what has been an enterprisingly offbeat season of Under the Sun, wanted us to gaze at a modern 18-year-old from new Japan who had decided to chuck in her architect's training in favour of becoming a geisha girl - or a geiko girl, as they are known in Kyoto, where she works.
The geisha tradition is hard for western minds to get to grips with and, I have to say, this programme did not help my grasp as much as I had hoped. On the one hand, the profession's formality and antiquity confer respectability on it. On the other hand, although the dance and music take four years to learn, by tradition, a geisha's ultimate accomplishment is the perfection of the art of giving sexual pleasure. In consequence, if your daughter announced that she wanted to be a geisha, you wouldn't know whether she was unmasking herself as a nerd or a prostitute.
Indeed, I am not sure if the parents of Mamehisa Tori-guchi, the subject of the film, knew. Her father had a go at explaining to the camera what geisha was, but only got as far as the words "special entertainment business" before his wife developed a terrible coughing fit.
He is an engineer. She sells life insurance. Both wore westernised outfits and haircuts, and innocently thought that their daughter had gone to Kyoto to look at the old temples as part of her architectural studies. Instead, she signed up with the proprietor of the Tama tea house, and Tama-san became her geiko "mother", a presumption that, understandably, alarmed Mamehisa's father. To all intents and purposes, their daughter was joining a cult whose first act was to obliterate in its recruits all signs of pre-existing personality. Mamehisa whitewashed out her features, replaced her clothes with kimonos and had her hair cut off.
For good measure, she was renamed. Mamehisa is the artist previously known as Mikiko. The obvious western comparison was with the induction of a nun.
Wigs, outfits and training are paid for by the geiko mother, who gets her investment back by not paying her protegees for their first three years of work for her. The tips are handsome, however, and, after the initial period, a new deal between employer and geisha is agreed upon. In due course, Mamehisa will have earned enough either to retire and marry, or to start her own tearoom. The commentary insisted that the geisha ends up "rich and powerful" - that rare thing, a financially independent Japanese woman.
The problem, obviously, is the arse you have to kiss to reach this nirvana. Most 18-year-olds have had quite enough of their parents without acquiring a second mother, still less a male "patron" who invests in your training and who, on your graduation day, is rewarded by your singing him a song about the sex that you have had with him (which you haven't). Then you get to the job itself, which turns out to be less about folk art and more about pouring drinks for middle-aged men, getting mildly tipsy, leading them in nursery-school games and refusing their advances. Mamehisa, I thought, was particularly good at rolling on the floor in mirth when they got fresh with her.
In 50 minutes, you do not expect to learn everything about a subject, but this film left too many questions unanswered. It made it clear that there was no hanky-panky allowed down at the Tama tea house, but it did not tell us if this is now the case everywhere. If it is - if all patrons bring their wives to the protegee's graduation ceremony, as Mamehisa's Mr Ikeda did - then this is an extraordinary instance of the ritual of sex replacing sex itself. But then, do red-blooded Japanese businessmen actually still fancy young women dressed up as Madame Butterfly? Or are they play-acting, too? We should have been told why the press turn up to take pictures when a new geisha joins a club. Is this titillation, a mark of respect or the equivalent of a photocall for a Bunny Girl, a celebration of nostalgia and kitsch?
But most negligently of all, we never learnt from Mamehisa herself why she had made this bizarre career decision. Here she was, a modern woman who enjoyed a tipple and bought rock music from Tower Records, yet who also prayed at the shrine of the woman/entertainment god and left her business card to remind "Bentin" to bless her. What did her friends think? What did she think of her clients? Was money the motive? There is no knowing how honestly she would have answered these questions - but Csaky's documentary did not even ask them. The way it stared at, rather than listened to, Mamehisa was almost as sexist as her profession itself.
Andrew Billen is a staff writer on the London Evening Standard