Japanese Numbers - Frequently Asked Questions

Sino: ichi (1), ni (2), san (3), shi or yon (4), go (5), roku (6), shichi or nana (7), hachi (8), ku or kyū (9), jū (10). Native: hitotsu, futatsu, mittsu, yottsu, itsutsu, muttsu, nanatsu, yattsu, kokonotsu, tō. The Sino set is the default in modern usage; native survives in counting general objects with 〜つ.

The Sino reading shi sounds identical to 死 (death). Yon, the native reading, is preferred when counting and in everyday contexts to avoid the unlucky homophone. Shi survives in compound words and time expressions: shi-gatsu (April), but yo-ji (4 o’clock).

After 10 (jū), build by combining: 11 = jū-ichi (10+1), 20 = ni-jū (2×10), 25 = ni-jū-go, 99 = kyū-jū-kyū. 100 = hyaku. The pattern is fully regular with sound-changes only at 300, 600, 800.

10,000 = 一万 (ichi-man). Japanese has no single word for "thousand" past 9,999. The next unit is man (10,000), so 100,000 = jū-man and 1,000,000 = hyaku-man.

Counter words (jōsūshi, 助数詞) attach to numbers when counting things. Different counters apply to different categories: 人 (nin) for people, 本 (hon) for long thin objects, 枚 (mai) for flat thin objects, 匹 (hiki) for small animals, 個 (ko) for general small objects. There are over 500 counters; about 12 cover most daily use.

The standard counter is 人 (nin). One person and two people are irregular: hitori (一人) and futari (二人). Three onwards uses nin: san-nin, yo-nin (note yo, not yon), go-nin, roku-nin, shichi-nin or nana-nin, hachi-nin, kyū-nin, jū-nin.

Four ways: Arabic numerals (1, 2, 3) dominant in modern horizontal text; kanji (一, 二, 三) common in vertical text and formal documents; hiragana (いち, に, さん) in textbooks and as furigana; the formal daiji (壱, 弐, 参) used on cheques and contracts to prevent forgery.

Mobile numbers are 11 digits (e.g. 090-1234-5678); landlines are 10 digits. Each digit is read individually. Use yon for 4 and nana for 7 (never shi or shichi - too easy to misshear). Zero is "zero" or rei in formal speech, "maru" in casual.

The counter is 歳 (sai). I am 25 years old = (Watashi wa) ni-jū-go-sai desu. The numbers 1 and 8 cause sound-changes: 1 year = is-sai, 8 = has-sai, 10 = jus-sai, 20 = hatachi (totally irregular).

Format: year + month + day, large to small. 2026年4月29日 = nisen-nijū-roku-nen shi-gatsu nijū-ku-nichi. The first ten days of the month use native readings: tsuitachi (1st), futsuka (2nd), mikka (3rd), and so on.

From largest to smallest: postal code, prefecture, city, ward, neighbourhood, chōme (block), banchi (sub-block), gō (building number), building name, room number. The reverse of Western order.

匹 (hiki) for small to medium animals: cats, dogs, fish, mice. 頭 (tō) for large animals: cattle, horses, elephants. 羽 (wa) for birds and (traditionally) rabbits.

1,000,000 = 百万 (hyaku-man), literally "one hundred ten-thousands". Japanese groups by 10,000 (man), so a million is "100 of 10,000" rather than "1,000 of 1,000".

〜つ (tsu) is the universal-fallback counter, derived from the native (Yamato) number system. Used 1 to 10 only (hitotsu, futatsu, mittsu...). After 10, switch to a specific counter or to 〜個 (ko).

いち (1), に (2), さん (3), し or よん (4), ご (5), ろく (6), しち or なな (7), はち (8), きゅう or く (9), じゅう (10). Hiragana carries the reading directly, so the dual readings of 4, 7, 9 are visible.

The reading shi for 4 sounds the same as 死 (shi, "death"). Hospitals and hotels often skip room 4. Gifts in sets of 4 are avoided. Yon is the alternative, used in counting to avoid the death-association.