The other day my wife was writing my name and address on a box she was going to send to our house in Japan. As she did so, she said, "P-chan," -- my nickname at home, which I inherited from an old cat we used to have, not the famous anime pig -- "I only have a red pen, so I'm going to write your name in red. Sorry about that." I didn't understand why she was apologizing, then I remembered the odd (from my viewpoint) superstition about writing people's names in red ink in Japan (and Korea). This may date from a practice in ancient Japan in which a samurai would send an official declaration to an enemy that he planned to kill, writing his opponent's name in his own blood. There are many other death-related superstitions in Japan. The number 4 is read shi, which is the same pronunciation as the kanji character death, and it's supposedly bad luck to give a person four of something -- hence, most gifts come in sets of five. It's sometimes considered bad luck to take a photograph with three people in the frame, as the one in the middle will be likely to die young, and some people will always make sure to avoid taking pictures with three subjects to avoid this taboo. Finally, it's considered bad luck to cut your fingernails at night, because you won't be able to be with your parents when they die. Superstitions can be fun!
If you write a person's name in red, something bad might happen.