As a general rule, Japan is very “about” — an English word the Japanese use to mean subtle, vague or imprecise — and a lot of information is not overtly stated. This can be a challenge to foreigners who aren’t used to having conversations in which the subjects of sentences are silently assumed by all parties. The Japanese also make use of euphemisms to stand for concepts they don’t want to talk about directly, like the famous word ecchi, the letter “H” said with a Japanese accent, which works as a general stand-in for anything sexual. If a guy thinks about girls too much, he is ecchi, and the most common way to refer to that particular human act is ecchi suru, lit. “to do H.” (If you watch the Japanese version of CSI: Miami, Horatio’s nickname of “H” is changed to “chief” for this reason.) Female menstruation is another subject that’s never talked about directly, and the usual way to refer to the subject is seiri, which just means “biology.” This word is so pervasive that I never learned the proper word in Japanese…until I discovered it by putting my foot in my mouth. I’d been talking with some friends about a brand of sake called Gekkei-kan but I mispronounced it, so that it came out gekkei, which just happened to be the Japanese word for “menstruation” (insert facepalm).
“That explains why Japanese tourists… *glasses* …always look at me funny.”