But take a peek in the shoulder bags this corporate army carries over its shoulders as it stands meekly in the crowded trains on the way to work. Whips, black leather garb and other S & M gear, mini-skirts that are more mini than skirt, feather boas, fancy lingerie and hair gel in industrial quantities.
Do not jump to premature conclusions. This is not evidence of some underground orgy network for bored office workers after hours. It is just the required wear for the rave clubs that have swept Japan in the past 12 months - loud, pulsing dance clubs where women flaunt themselves on raised platforms and men squirm to get a better view.
Sometimes it gets out of hand: the trend-setting Juliana's in Tokyo, set up by a British company, has already tried to tone things down after an impromptu striptease nearly caused a riot on the dance floor. But other clubs are springing up, one more outrageous than the next.
Everything is for show: the whips and feathers are dance accessories, the clothes are cut to reveal more than they conceal. This is the home of the miniscule T-back, and more recently the O-back panty style. The raised platforms, or otachidai, frequently resemble shows of designer swimwear collections. The tanning salons that have become popular in Japan owe their existence in no small part to these dance clubs, and the amount of flesh that is put on show. The latest rave location in Tokyo is Ronde Club, where the S & M theme is more pronounced and the women's clothing even more skimpy.
So much for the image of the bashful Japanese geisha, smiling coyly behind her fan. Something has happened to Japanese womanhood. Obeisant by day in their offices, by night these women exult in standing out, showing off, and competing with the other women on the platform. None of this behaviour accords with the textbook definition of 'Japaneseness'. Men go to these clubs as well, but mostly to ogle. Their gesture towards trendiness is hair gel: most are still wearing suits and ties.
Probably the single biggest change is diet: with their increasing affluence and the influx of Western eating habits, Japanese have become consumers of meat and milk. As a result, girls of today are growing up with longer legs and bigger busts and have suddenly discovered that it is all right to be proud of their bodies. The old bow-legged (in Japanese the term is 'radish-legs'), flat-chested stereotype is gone. Affluence has also given young women the chance to spend more money on cosmetics, clothes and mind-broadening travel.
This new-found confidence has spilt over into the world of marketing. Fashion advertisements, which for decades used Western women as idealised beauties to sell Japanese products, are now increasingly using Japanese models. Cosmetic surgery to make eyes and noses look 'more Western' is a declining fad.
To be sure, the women will be at work the next morning, bowing reverently to their boss as they serve him his first cup of tea. And when they eventually get married they may indeed make huge sacrifices for their children's education and their husband's career. But the self-effacing shame of the 'radish legs' is disappearing within a single generation.