Stop it! Japan anti-groper app becomes smash hit

Groping on trains can occur in any country where trains are frequently crowded. But the idea that men are superior to women, which is Japan's traditional bias, may help sustain" sexual harassment on trains in the country.

Awareness of the issue has risen in Japan in recent years, with women exchanging tips on how to avoid the unwanted attention online.

East Japan Railway runs women-only carriages during rush hours and has set up security cameras on some lines notorious for a high rate of groping.

Offenders face up to six months in jail or fines of up to 500,000 yen ($5,500 dollars).

The potential jail sentence is increased to 10 years if violence or threats are used.