I saw plenty of men and women reading the thick comic type, I believe it was
Etchy Manga (That MMM mentioned) on the train, the type with definite pornography, although they were drawings, not real life photos.
It seemed to be rather common and simply part of a Japanese
thing.
I'm not 100% sure what the consensus in peoples minds were, possibly art, possibly appreciating the drawing excellence, or simply fantasizing about the activities.
The thing that concerned me was the age of the people reading it, mature adults. If it was young teenagers having a laugh, I could have understood that.
I also saw plenty of magazines being browsed upon that did have naked ladies on some pages, although never naked men.
The reader would often half close the page and do an eye sneak to get a gander.
As for full real life pictures pornography, never saw it on the trains, but definitely used to see it right near where I would park my scooter by way of a vending machine with a pink curtain covering the contents of the goods for sale.
Love hotels, I wasn't offended, and found them to be a novelty, and like R.Samurai, I have a good collection of photos from on the road. The designs were just something I'd never seen back home
