Japanese superstitions

Japanese superstitions are rooted in the culture and history of Japan and the Japanese people. Some Japanese superstitions are meant to teach lessons or serve as practical advice.
Overview
Some superstitions that are common in Japan have been imported from other cultures. The Japanese share superstitions with other Asian cultures, particularly the Chinese, with whom they share significant historical and cultural ties. The unluckiness of the number four is one such example, as the Japanese word for "four" 四 romaji: shi is a homophone for "death" kanji: 死. The same is true for Chinese, hanzi: 死 pinyin: sǐ, is also homophonous to "death." However, unlike most other countries, in Japan, a black cat crossing one's path is considered to bring good luck.
A significant portion of Japanese superstition is related to language. Numbers and objects that have names that are homophones for words such as "death" and "suffering" are typically considered unlucky (see also, Imikotoba). Other superstitions relate to the literal meanings of words. Another significant part of Japanese superstition has its roots in Japan's ancient pagan, animist culture and regards certain natural things as having kami. Thus, many Japanese superstitions involve beliefs about animals and depictions of animals bringing about good or bad fortune.
Folk wisdom
Resting just after eating results in becoming a cow/pig/elephant. (This discourages laziness.)
If whistling or playing a flute at night, snakes will come out. (This means not to bother the neighbors.) In this context, "snake" means a thief.
The first dream of a Japanese New Year will come true (hatsuyume).
Breaking a comb or the cloth strap of a geta wooden sandal is an omen of misfortune.
Linguistic superstition
If a funeral hearse drives past, one must hide one's thumbs in a fist. The Japanese word for "thumb" literally translates as "parent-finger". Hiding it is considered protection for one's parents. If this is not done, one's parents will die.
Numbers
Lucky numbers
7 is an important number in Buddhism, and is also considered lucky.
8 is considered a lucky number due to its shape.
Unlucky numbers
There are six unlucky numbers in Japanese. Traditionally, 4 is unlucky because it is sometimes pronounced shi, which is the word for death. Sometimes levels or rooms with 4 do not exist in hospitals or hotels. Particularly in the maternity section of a hospital, the room number 43 is avoided because it can literally mean "stillbirth". (死産 - shizan: 死 - death/to die and 産 - childbirth/produce). In cars and racing, number 42 which sounds like shini (死に – to death) and 49, which sounds like shiku (死苦 - a painful death) are avoided. When giving gifts such as plates, they are normally in sets of three or five, never four.
Number 9 is sometimes pronounced ku — with the same pronunciation as agony or torture. Combs (kushi) are rarely given as presents as the name is pronounced the same as 9.
Due to these unlucky connotations, the numbers 4 and 9 are often pronounced yon and kyuu instead.
The number 13 is occasionally thought of as unlucky, although this is imported from Western culture.
Death and the supernatural
After a Japanese funeral, the mourners perform a cleansing ritual by throwing salt over themselves or scattering it on walkways leading to the front door.
Sleeping with head to the north results in a short life. (This is the way a body is laid out at funeral.)
Chopsticks should not be stuck upright into food, especially rice. Chopsticks are only stuck upright into rice in the bowl on the altar at a funeral or when paying respects to the deceased. This is called hotokebashi.
When sharing food, items should never be passed from chopstick-to-chopstick, as this is done only in a ceremony where bone fragments from cremated remains are placed in an urn.
Cutting fingernails or toenails at night is bad luck. If one does so, it is believed that they will not be with their parents at their deathbed.
A person's name should not be written in red ink. (This is due to names on grave markers being red.)
Animals
Use of the Maneki Neko or "lucky cat". Many businesses such as shops or restaurants have figures of such beckoning cats, which are considered to be lucky and to bring in money and fortune.
A spider seen in the morning means good luck so the spider should not be killed. If a spider is seen at night means bad luck so it should be killed.
A crow's caw means something bad will happen. This can be anything from illness or accidents to death or natural disasters.
See also
Japanese mythology
Shinto
Japanese Buddhism
List of haunted locations in Japan
Dajare
References