We’ve all heard the horror stories. It happened to a friend of a friend, maybe a classmate or coworker. Maybe it even happened to you.

Rush hour in Japan, and in Tokyo particularly, is rough for many reasons. Most people worry about the excruciating heat, being forced into uncomfortably squashed positions and not being able to get out of the carriage in time. Women have one more thing to worry about: chikan, which literally translates as molester or pervert. One quick Google search will tell you that it is unfortunately a very real issue in Japan.

To prevent these events from occurring, various railway companies started designating women-only cars in the early 2000s and many suspect that Japan’s shutter sound ban on mobile phones a few years later was meant to scare off molesters from taking pictures under female students’ skirts.

This week, stamp-maker Shachihata launched a trial run of a new product intended to help fight the sexual harassment issue: an “anti-groping” UV stamp.

The stamp uses special ink that can only be seen under UV light, allowing victims to identify their aggressors without having to resort to physical assault. This was an issue brought to light a few months ago when a video of two students chasing an alleged groper went viral. Many made the case that a man who tripped up the runaway committed a crime despite his effort to help the two girls catch their harasser.


The first 500 sets of the anti-groping UV stamp, priced at ¥2,500 each, sold out on Tuesday in under one hour – within 30 minutes, to be exact, proving further that security against these types of predators is much in demand. When pressed onto the skin of an offender, the stamp leaves a nine millimeter seal mark in the shape of an open palm, which is visible under UV light. The black light that is sold with the stamp is used to illuminate the stamped mark. A Shachihata spokesperson said that the product is meant to work primarily as a deterrent.

While Japanese police haven’t addressed the impact of or need for the product, Shachihata has said they hope to officially release the product to all once it’s been revamped following trial user feedback.