When 4 is Yon, When It Is Shi (Reading Variations)
Three Japanese numbers have two readings: 4 (shi or yon), 7 (shichi or nana), 9 (ku or kyū). The reason is partly historical and partly superstitious. This page tells you exactly which reading to use in which context.
Quick reference: the three pairs
| Numeral | Sino reading 1 | Sino reading 2 | Native | Default in counting |
|---|---|---|---|---|
| 四 (4) | shi (し) | yon (よん) | yo (よ) | yon |
| 七 (7) | shichi (しち) | nana (なな) | - | nana |
| 九 (9) | ku (く) | kyū (きゅう) | - | kyū |
Context-by-context lookup
| Context | 4 | 7 | 9 | Notes |
|---|---|---|---|---|
| Counting in isolation | yon | nana | kyū | most common case |
| Time, hours (o’clock) | yo-ji | shichi-ji | ku-ji | all three revert to older readings |
| Time, minutes | yon-pun | nana-fun | kyū-fun | minute counter is irregular too |
| Months | shi-gatsu | shichi-gatsu | ku-gatsu | older readings stuck for months |
| Days of the month | yokka | nanoka | kokonoka | native readings entirely |
| Years (-nen) | yo-nen | nana-nen | kyū-nen | |
| Age (-sai) | yon-sai | nana-sai | kyū-sai | 20 is hatachi, irregular |
| Phone numbers | yon | nana | kyū | always; avoid mishearings |
| Prices (-en) | yon-en | nana-en | kyū-en | |
| People (-nin) | yo-nin | shichi-nin / nana-nin | kyū-nin | both shichi-nin and nana-nin OK |
| Long objects (-hon) | yon-hon | nana-hon | kyū-hon | |
| Flat objects (-mai) | yon-mai | nana-mai | kyū-mai | |
| Compound words / idioms | shi (often) | shichi (often) | ku (often) | older readings preserved |
Why 4 is considered unlucky
The reading shi for 4 sounds identical to 死 (shi, "death"). The same superstition exists across China, Korea, and Japan. Hospitals often skip room 4. Hotels and elevators sometimes label the fourth floor as 5 or as F. Gifts in sets of four are avoided. The number 9 has a milder unlucky association via ku (苦, "suffering"). 7, by contrast, is often lucky in Japan, thanks to 七福神 (shichi-fuku-jin), the seven gods of fortune.
Why the older readings survive in months
The names of the months were fixed in classical Chinese-influenced Japanese, when shi-gatsu, shichi-gatsu, and ku-gatsu were the standard readings. The names froze. So 4月 stays shi-gatsu even in modern Japanese where "4 of anything else" is yon. The same is true of times: 4 o’clock is yo-ji (a third reading, the native yo, neither shi nor yon), 7 o’clock is shichi-ji, 9 o’clock is ku-ji.
Frequently asked questions
Why does 4 have two readings in Japanese?
The Sino-Japanese reading shi (し) was borrowed from Chinese alongside the kanji 四. Shi sounds identical to 死, the kanji for death. To avoid the unlucky homophone, Japanese revived the native reading yon (よん) for counting. Both readings remain in use, but yon dominates everyday counting and shi survives in fixed compounds.
When should I use shi instead of yon?
Shi is the standard reading in: month names (4月 shi-gatsu, April), some compound nouns (四季 shi-ki, four seasons; 四角 shi-kaku, square), some idioms. Outside compounds, default to yon for counting, ages, prices, phone numbers, and most counters.
What about 7? Is shichi or nana the right reading?
Both are valid. Nana is preferred when counting in isolation, in phone numbers, and with most counters. Shichi survives in 7月 (shichi-gatsu, July), 7時 (shichi-ji, 7 o’clock), and the festival 七五三 (shichi-go-san). For people, shichi-nin and nana-nin are both acceptable.
When do I use ku versus kyū for 9?
Kyū is the default for counting and most counters. Ku appears in 9月 (ku-gatsu, September), 9時 (ku-ji, 9 o’clock), and a few set phrases. Like shi, ku is associated with negativity (it sounds like 苦, suffering) so kyū is the safer choice in most contexts.
Why is 4 considered unlucky in Japan?
The shi reading sounds identical to 死 (death). Hospitals and hotels often skip room 4. Gifts in sets of four are avoided. The same superstition exists in China and Korea (tetraphobia). 9 has a milder unlucky association via ku (苦, suffering), and 7 is the opposite, lucky, via 七福神 (shichi-fuku-jin, the seven gods of fortune).
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