A group of men boarded the women-only car of the Chiyoda Line subway in Tokyo during the morning commute on Feb. 16 as a form of protest, saying that excluding men was a form of discrimination. Such protests are not unusual, but the media almost never covers them. In this case, the women who were already on the train objected loudly, but the men refused to leave after the train arrived at Kokkai-gijidomae Station, thus prompting station staff to become involved. Then, one of the protesters pushed the emergency stop button on the platform. The train ended up being delayed by more than 15 minutes.

Now that was news, so when one of the leaders of the anti-women-only car movement, a man called “Dr. Sabetsu” (“Dr. Discrimination”), tried to speak publicly in front of Shibuya Station on Feb. 24, the press was on hand. This is exactly the kind of publicity the movement has been trying to attract for years. Dr. Sabetsu said that discrimination is discrimination, regardless of the reason, and that men had every right to ride on any train car they wanted to.

The reason for women-only train cars is chikan — sexual molestation or groping — a problem as old as rush hour itself and one that Japan has never been able to solve. Starting around the turn of the century, some train lines in Tokyo introduced women-only cars as an option on some evenings, mainly at the request of the Metropolitan Police Department.

As media critic Maki Fukasawa explained on the Feb. 27 edition of Bunka Hoso’s “Golden Radio,” although there has been a movement against women-only cars ever since they were introduced, it has become more visible in recent years thanks to the rise of social media, which allows for better coordination among men who want to protest.

It’s important to remember that men are not legally prohibited from entering these cars. They are simply asked not to use them during rush hour. Railways are counting on passengers’ good will, so protesters know they can cause disruptions by just trying to board. The women on the train may object, but they are usually more concerned with getting to work on time. These protest groups have also sued railways for discrimination, but have never won in court.

The chikan issue didn’t make headlines until 1988, when a woman on the Midosuji Line in Osaka saw a man groping a girl and told him to stop. Angered, the man intensified his attack and then he and another man dragged the girl off the train, took her to a construction site and raped her. No one stopped them. Fukasawa was a student at the time and wrote a paper on the incident. She says that what people took away from the story was that it was better to say nothing.

Over the years the media have been more likely to cover the chikan issue when it’s found that a woman has made a false accusation against a man, a situation immortalized in Masayuki Suo’s hit 2006 film, “I Just Didn’t Do It.” Last May, the media was all over a story about a man who, trying to escape after being accused of groping, was killed by a passing train.

Until the mid-1990s, railways resisted even using the term “chikan,” preferring the milder “shōbōryoku” (nuisance) or “meiwaku” (annoyance). And while “chikan is a crime,” as in-car posters now point out, until last year’s passage of stricter sex assault laws, a woman had to formally press charges for an alleged attacker to be arrested.

Fukasawa says that less than 10 percent of train groping victims actually report their attacks. The reasons are various, but mainly have to do with the fear of not being believed or of arriving late to work. Meanwhile, underground groups of chikan trade tips on the internet about the best times and places to partake of their pastime.

Fukasawa says that women-only cars were not introduced to discriminate against men in general, but, in practice, they do. However, given the nature and prevalence of the problem — some women are terrified of rush hour — there doesn’t seem to be any other solution. JR’s Saikyo Line, which produces more reports of chikan than any other, installed cameras in 2009 to catch attackers in the act, and while the number of reports decreased, they haven’t disappeared.

According to Akiyoshi Saito, who manages a mental health program and wrote a book about the subject, some men have a compulsion to grope. In an interview with Asahi Shimbun, he explained that his main goal is to prevent recidivism among men who have committed chikan crimes. Unlike the general image, these men are mostly university graduates with good jobs and families, and their preferred targets are what he describes as unassuming women. Groping is a power game. The excitement has less to do with sex than with letting off steam and getting away with something. They are addicted to groping.

If that’s the case, then the best solution would be relieving passenger congestion, since these men count on the cover of crowds. Train groping is not limited to Japan. It happens all over the world. If it seems to be more prevalent in Japan it’s because of the long, cramped commutes that make it easier for these men to get away with furtively touching women.

The Asahi Shimbun suggests that the Japanese word “chikan” is becoming the preferred term internationally for this phenomenon.

Is it possible to eradicate groping? Professor Kazue Muta of Osaka University Graduate School, a specialist in gender theory who was also interviewed by the Asahi, doesn’t think so, but in any case the situation has never been properly studied because groping isn’t taken seriously in Japan. The basis of all sex crimes against women is a deep-seated belief that men are superior, which makes it easier to “trivialize” train groping. Japan’s sex education program doesn’t address gender dynamics and the attendant rights of individuals.

Society thinks it’s scarier for men to be falsely accused of groping, no matter how rarely that happens, than it is for women to be groped on a daily basis.