21/02: No tattoos in the onsen in Japan!
Many onsen (public baths) in Japan have very strict rules about tattoos: nobody with a tattoo is allowed in. The picture above is from the onsen we often take students to, close to the school. The text above the evocative picture says 入れ墨禁止 (irezumi kinshi, or tattoos forbidden).
This picture was the only English text visible in the entrance of an onsen!
The original reason for this ban was to keep out ヤクザ (yakuza), or members of other 暴力団体 (violence groups). However, this obviously doesn't apply to most foreigners. While onsen employees obviously don't perform full-body checks before letting people in, there is still a chance that you would be asked to leave if another patron complained about your tattoo. In one case, a young, red-haired English girl we know was thrown out of an onsen because of a small tattoo on her lower back, despite her obviously not being a member of a violence group. If you have tattoos and you're coming to Japan, you may have to apply a band-aid before you go for a bath...