How technology can help stop groping on public transport

While changing attitudes to ensure it doesn't happen in the first place, Japan is taking yet more measures to tackle a serious problem

Groping on public transport is a problem the world over, but the scale of it in Japan, where it is known as "chikan", is infamous. According to Tokyo's metropolitan police department, 1,750 cases of groping or molestation were reported in 2017, with more than 50% of sexual harassment cases occurring on trains, and a further 20% in train stations. Some reports suggest that more than 75% of all Japanese women have been groped.

No wonder women there are looking for a deterrent. Introducing the latest gadget: a stamp that brands gropers with invisible ink, which police can then reveal with UV light. It is the latest measure to try to fix the problem. Others have included women-only train carriages - which are still occupied by groups of men in protest, despite having been introduced over two decades ago - and an app that enables victims to play a voice shouting "Stop it!" at ear-piercing volume or bring up a full-screen message reading: "There is a molester. Please help," to other passengers.