I've talked before about how the Japanese can be quite superstitious at times, and since today is Friday the 13th, I thought I'd revisit some of the more interesting folk beliefs here. Such as, don't urinate on a worm, or he'll get revenge by making your private parts swell up. Don't whistle at night or a snake will come, and don't play with fire or you'll wet the bed. When you sneeze twice, it means someone is gossiping about you, a joke that pops up in anime quite a lot. If you see a spider in the morning, it's good luck, so don't kill it. If you want to check the weather tomorrow, throw your shoe as far as you can; if it lands sole down, it will be sunny, but if upside down, it will rain. Being such a death-oriented place, there are a lot of related superstitions. When you attend a funeral you'll be given a packet of salt by the funeral home, and you must throw the salt over your body to cleanse it before crossing the threshold into your house or the spirits of the dead will move in. Don't cut your fingernails at night, or you won't be able to be with your parents on their deathbed. Don't write someone's name in red ink, or you'll shorten their life. Finally, if you see a hearse, you should hide your thumbs inside your fists, or one of your parents will die (this is due to the fact that the word for thumb in Japanese means "parent finger").
Oh, they know about Friday the 13th, but mainly associate it with the classic horror film only.
Japan has many interesting superstitions.