What could possibly have attracted us to a Japanese photobook of secretly shot sexual activities on the Tokyo Metro? Yes. It was the blue, pink and purple colourway of the cover design.

The photographer is Ikko Kagari. He shot quite a few books like this and even published a technical manual on how to photograph women covertly with infrared cameras. Charming!

Of course we can't help but look at the clothes. It's very stylish. This looks like a lost Comme campaign by Deborah Turbeville.

A little more American Apparel. It is a sexy book and as this link shows, Kagari's infrared camera finds all the hot spots.

Mind the gap. We can not recommend trying out any of these moves on the London Underground. There is nothing sexy about the Central Line and a sharp crack to the head with a Kindle would no doubt be the result.

Published in 1994. The title roughly translates as Pervert Rush. It's a fair description. Sometime in the 2000s, women only carriages were introduced on the Tokyo Metro. The infrared in flagrante scene was over.