Numbers in Chinese-speaking communities carry meanings that come mostly from language and from older cosmological schemes, not from any property of the numbers themselves. What follows describes beliefs and customs that people hold, and how those ideas arose. It does not claim that any number brings luck, wealth or harm. Practice also varies between Mandarin-speaking and Cantonese-speaking regions, between generations, and between individuals, many of whom give these ideas little thought.
Two sources of meaning: sound and system
The first source is sound. Standard Chinese has a relatively small inventory of syllables, so many unrelated words sound alike or nearly alike. Wordplay on this fact is an old and affectionate part of the culture, and it shows up in New Year pictures, festival foods, gift choices and names. Numbers are short, common words, so they are easy targets for this kind of punning. Individual digits are the subject of the study of Chinese number homophones, and the broad point here is simply that a number can be liked or disliked because of the word it resembles.
The second source is system. Commentaries associated with the Yijing (Book of Changes) treat odd numbers as yang and even numbers as yin, and later thinkers built elaborate correspondences between numbers, directions, seasons and the five phases. These schemes are philosophical and divinatory frameworks, not measurements. They matter here because Feng Shui draws on them, as discussed below.
The lucky eight
Eight is the best-known case. In Cantonese, the word for eight (baat) rhymes with the word for “to prosper” or “to get rich” (faat), as in the greeting associated with the New Year, “gung hei faat choi”. In Mandarin the two words (bā and fā) are less alike but still close enough that the association carried over, especially after the Cantonese-speaking commercial centres of Hong Kong and Guangdong became influential in the late twentieth century. The pairing is usually summarised as eight and prosperity, and it is a matter of wordplay. Nothing about the quantity eight is supposed to produce anything.
Over time the association spread to dates, prices, addresses and telephone numbers. Combinations such as 168 are often explained as sounding like “all the way to prosperity”, and 518 is sometimes read as sounding like “I want to prosper”. These readings are playful and rely on sound, so they work best in particular dialects.
The unlucky four
Four is the mirror image. The word for four (sì in Mandarin, sei in Cantonese) sounds similar to the word for death (sǐ, sei). In Mandarin the tones differ, but the resemblance is enough for many people. The same sound link exists in Japanese and Korean, where the number words were borrowed from Chinese, and the habit of avoiding the digit is sometimes called tetraphobia in East Asia. Buildings that omit a fourth floor, and hospitals or hotels that skip rooms numbered with a four, are the commonly cited examples. Not everyone follows the custom, and its strength varies from place to place.
Six, nine and the rest
Other digits have milder reputations, mostly from the same source.
- Six (liù) resembles the word for “flow” or “smooth” (liú), as in the well-wishing phrase for things going smoothly. In online slang, “666” is used as praise.
- Nine (jiǔ) resembles the word for “long-lasting” (jiǔ), and it is also the highest single-digit yang number, which is why it has been tied to emperors and to the Double Ninth Festival.
- Seven (qī) has a mixed reputation, because it sounds like several unrelated words, and it appears in both the romantic Qixi date and the seventh lunar month, which is traditionally linked with ghosts.
Writers often say that three (sān, saam) resembles the word for “life” or “birth” in Cantonese, though this is less central than the eight and four examples.
Feng Shui as an application
Feng Shui is a Chinese tradition concerned with arranging buildings, rooms and graves in relation to landforms, water, direction and the flow of qi. Its roots are old, and some later texts were attributed to early writers, though the history is hard to pin down. Practitioners use numbers in several ways. The nine-cell Lo Shu square, a cousin of the magic squares known from other mathematical traditions, assigns a number to each compass direction. The Flying Star method moves those numbers around a building according to its date of construction and orientation. Some practitioners also read house or phone numbers by their digits, in the same way as the sound-based customs above. Details differ between schools, and the many Feng Shui number traditions do not always agree with one another. These systems are not supported by scientific evidence, and they are best understood as a cultural and aesthetic practice with a long history.
How the beliefs play out in public life
The most visible effect is commercial. Telephone numbers, car registration marks and street numbers rich in eights tend to attract a premium in some markets, and numbers with fours are often discounted. This market for auspicious phone numbers exists because enough buyers share the belief, which is a social fact and not evidence that the numbers do anything. Dates are also affected: the Beijing Summer Olympics opened on 8 August 2008 at 8:08 pm local time, and many weddings reportedly took place on that date.
Seeing it in context
Chinese-speaking communities are not unique in attaching meaning to digits. Many cultures treat some numbers as fortunate and others as unfortunate, a theme that appears in any comparison of unlucky numbers across regions. What distinguishes the Chinese case is how directly the preferences follow from the sounds of the number words, along with a long tradition of cosmological number schemes. Because the preferences rest on language, they travel imperfectly: a number can be favoured in Cantonese, neutral in another dialect and unremarkable in a language where the sound link does not exist.
Reading the topic this way keeps the focus on what people believe and why, and it leaves open the question of how much weight any individual gives to it. For most people today it is a mix of tradition, humour and habit.