Japan's capital is facing an epidemic of men who can't keep their hands to themselves, and it's happening inside one of its most famous symbols -- the trains.
Whether above the crowded streets or below ground, Tokyo's trains are renowned for their efficiency and cleanliness.
But according to a survey conducted in Tokyo last year, nearly 64 percent of Japanese women in their 20s and 30s said they've been groped on trains, subways or at transit stations in the city.
These subway gropers -- who lean, rub and pinch during the remarkably crowded rush hours -- are known in Japanese as "chikan."
Victims are often ashamed to show their faces. They say the experience is degrading, humiliating and frightening, but most are too embarrassed to react when it's happening.
"They think it's a kind of shame to say something or to cry, 'Help, help,'" said Mihoko Ejiri, a professor at Tsuda College of Women.
But now, there is some temporary relief for Japanese women -- a train car of their own. It's just an experiment now, and only during rush hour, but for those who have been harassed, it has made a huge difference.
One woman passenger told ABC News, "Because it's just only girls, females, and we don't touch, you know, so … [it's] very safe!"
Even most men seem to think the women-only cars are fair. Many men worry about being falsely accused of groping if they accidentally brush up against a woman in a packed train. Gropers can be imprisoned for up to seven years or fined up to $485.
But there's also some grumbling, especially in overcrowded adjacent cars, where the men are packed like sardines, while the ladies ride in comfort.
However, as one newpaper editorial in Tokyo suggested, the victims did not bring about the women-only experiment, but the "chikan."