Why Is the Number Four Unlucky in Japan?

The short answer

The number four (四) can also be read "shi", which sounds the same as the word for death (死, shi), so it has long been considered unlucky. In the same way, nine (九, ku) sounds like the word for suffering (苦, ku), so 4 and 9 are the classic "imikazu", numbers best avoided.

That said, not many people fret every time they see a 4 in daily life. It is mainly avoided in situations where calling "death" or "suffering" to mind could upset someone, such as hospital room numbers and celebration gifts.

A matter of language: it sounds like "death"

Japanese numbers mix readings that came from China (on'yomi) with native Japanese readings (kun'yomi). The on'yomi of 4 is "shi" and the kun'yomi is "yo" (or "yon"). Dictionaries explain imikazu as "four (death), nine (suffering) and so on", and besides 4 and 9, 42, which can be read "shini" (to die), has also been disliked.

This feeling is not unique to Japan. In Chinese and Korean too, 4 sounds the same as or similar to "death", so 4 is disliked in China, South Korea, Taiwan, Hong Kong and elsewhere. In China, however, 9 sounds the same as 久 (a character meaning "long-lasting") and is considered lucky because it suggests something that endures, the opposite of Japan. In Taiwan too, 9 is lucky, and the ninth day of the ninth month of the lunar calendar is a day for honouring older people. Four is reportedly also disliked in Singapore and Malaysia, which have large Chinese communities. In China, 14 and 24 are also said to be avoided because they sound like "certain to die" and "easy to die". In South Korea, some buildings have no fourth floor, or show the fourth-floor lift button as "F" (for "four"), and Incheon International Airport is said to have no gates 4 or 44.

It is not clear when the habit of avoiding 4 began. A report by the NLI Research Institute, a private think tank, points out that old Shinto does not seem to have disliked 4. For example, the etiquette for worship at Izumo Taisha shrine is "two bows, four claps, one bow", with four claps of the hands. The same report also says that in the Heian period, people seem to have avoided reading 4 as "shi" and called it "yo" instead.

Incidentally, according to an encyclopaedia, the idea of numbers being lucky or unlucky exists all over the world, and in Japan there are examples of 8 being treated as a sacred number, as in "yaoyorozu no kami" (the eight million gods), because the character 八 widens towards the bottom, suggesting growing prosperity. Rather than 4 being singled out, it is one example of a habit of reading meaning into the "sound" or "shape" of numbers.

The curious character for four, and how Japanese counts

The kanji numerals 一, 二 and 三 (one, two, three) show their value with that many horizontal lines, so why is 4 written 四? According to the NLI Research Institute report, in ancient scripts such as oracle bone script, 4 was written with four horizontal lines, but partly because four lines were hard to read, 四, a character that originally meant something else, came to be borrowed for 4 because it had the same pronunciation.

Counting has some interesting features too. Under NHK's broadcasting guidelines, 4, 7 and 9 are as a rule read "yon", "nana" and "kyū". But when counting up in order, "ichi, ni, san...", the readings "shi", "shichi" and "ku" are also used. In other words, Japanese people naturally switch between two readings depending on the situation.

Where 4 is still avoided today

Traces remain in the language itself. In many words, such as "yokka" (the 4th day), "yonen" (four years) and "yonkai" (four times), 4 is read "yo" or "yon" rather than "shi". NHK also reads the number 4 as "yon" as a rule (with "shi" also allowed). This is partly to prevent mishearing, however, since "shi" is easily confused with "shichi" (7). On the other hand, words that read 4 as "shi", such as "shiki" (the four seasons) and "shihō" (all four directions), are in perfectly normal use.

In buildings, numbers containing 4 are sometimes skipped in flat numbers. Hospitals in particular are said to often avoid room numbers with 4 and with 9, which suggests "suffering". While buildings with no fourth floor at all are not unusual in China and South Korea, leaving out the fourth floor is reportedly not very common in Japan.

Car number plates are affected too. In the standard allocation of numbers, the last two digits "42" (shini, to die) and "49" (shiku, death and suffering) are not used. They can, however, be requested through the "kibō number" system, which lets you choose your own number. Incidentally, the number plates of private cars and other vehicles owned by people without Japanese nationality reportedly do not use 13 either, the number disliked in the West.

Even in the stacked boxes (jūbako) used for osechi, the traditional New Year food, there is a custom of calling the fourth tier not "shi no jū" but "yo no jū", written with a different character (与).

Gift etiquette and odd and even numbers

Gifts are where 4 and 9 are most clearly avoided. Gift guides from department stores and Japan Post say that an odd number of items is preferable, and that the basic rule is to avoid 4 (death) and 9 (suffering).

This is also linked to ideas about odd and even numbers. In the yin-yang thought of ancient China, odd numbers are "yang" and even numbers "yin", and at Japanese celebrations odd numbers, which "cannot be divided", are preferred, while even numbers tend to be avoided because they suggest "splitting" or "parting". Pairs (2), half-dozens (6) and dozens (12) count as a single set, however, so they are fine, and 8 is considered lucky because the character 八 widens towards the bottom.

There are also wordplay taboos that have nothing to do with numbers. A comb (kushi), for example, calls to mind "ku" (suffering) and "shi" (death), so it is said to be unwelcome as a celebration gift.

What puzzles visitors from abroad

In the West, 13 is the well-known unlucky number, but in Japan the ones to really watch are 4 and 9. In Christian culture, meanwhile, 4 is linked to the cross and the four Gospels and is sometimes even considered a good number. It is fascinating how different the image of a number can be from one country to another.

When travelling, you are only likely to notice 4 and 9 in hospital and flat room numbers, car number plates and the number of items in a gift. When choosing an assortment for souvenirs or gifts, avoid packs of 4 or 9 and choose an odd number, or a number that counts as a set, such as a pair or a dozen, and you will be fine.

Even so, there is no need to be overly anxious. Department store gift guides also say that attitudes differ between regions and families and that there is no need to be terrified of breaking the rules. It is enough to know about it and take a little care with gifts and hospital visits.

Tips

When giving gifts or souvenirs, avoid packs of 4 or 9 and choose an odd-numbered assortment, such as 3 or 5, to be safe.
When visiting someone in hospital, take particular care with 4 and 9. It is also safest to avoid items that call to mind "death" or "suffering".
When saying the number 4 out loud, "yon" sounds natural. The 4th day of the month is read "yokka".
If you cannot find room 4 or room 9 in a block of flats or a hospital, it is not a numbering mistake.
Hardly anyone worries about a 4 in everyday shopping or phone numbers. Do not overthink it; just be considerate when the situation calls for it.