Japanese numerals

The Japanese numerals are the number names used in Japanese. In writing, they are the same as the Chinese numerals, and large numbers follow the Chinese style of grouping by 10,000. Two pronunciations are used: the Sino-Japanese (on'yomi) readings of the Chinese characters and the Japanese yamato kotoba (native words, kun'yomi readings).

Basic numbering in Japanese[]

There are two ways of writing the numbers in Japanese: in Arabic numerals (1, 2, 3) or in Chinese numerals (一, 二, 三). The Arabic numerals are more often used in horizontal writing, and the Chinese numerals are more common in vertical writing.

Most numbers have two readings, one derived from Chinese used for cardinal numbers (On reading) and a native Japanese reading (Kun reading) used somewhat less formally for numbers up to 10. In some cases (listed below) the Japanese reading is generally preferred for all uses. Archaic readings are marked with †.

* The special reading 〇 maru (which means "round" or "circle") is also found. It may be optionally used when reading individual digits of a number one after another, instead of as a full number. A popular example is the famous 109 store in Shibuya, Tokyo which is read as ichi-maru-kyū (Kanji: 一〇九). (It can also be read as 'ten-nine'—pronounced tō-kyū—which is a pun on the name of the Tokyu department store which owns the building.) This usage of maru for numerical 0 is similar to reading numeral 0 in English as oh. However, as a number, it is only written as 0 or rei (零). Additionally, two and five are pronounced with a long vowel in phone numbers (i.e. にい and ごお nii and goo).

Starting at 万 (10,000), numbers begin with 一 (ichi) if no digit would otherwise precede. That is, 100 is just 百 hyaku, and 1000 is just 千 sen, but 10,000 is 一万 ichiman, not just *man. (This differs from Chinese, where numbers begin with 一 if no digit would otherwise precede starting at 100.) And, if 千 sen directly precedes the name of powers of myriad, 一 ichi is normally attached before 千 sen, which yields 一千 issen. That is, 10,000,000 is normally read as 一千万 issenman. But if 千 sen does not directly precede the name of powers of myriad or if numbers are lower than 2,000, attaching 一 ichi is optional. That is, 15,000,000 is read as 千五百万 sengohyakuman or 一千五百万 issengohyakuman, and 1,500 as 千五百 sengohyaku or 一千五百 issengohyaku.

As noted above, yon (4) and nana (7) are preferred to shi and shichi. It is purported that this is because shi is also the reading of the word 死 ("death") which makes it an unlucky reading; while shichi may sound too similar to ichi (1), shi or hachi (8). However, in quite a number of established words and phrases, shi and shichi are preferred; additionally, when counting (as in "ichi, ni, san, shi,..."), shi and shichi may be preferred.

The numbers 4 and 9 are considered unlucky in Japanese: 4, pronounced shi, is a homophone for death (死); 9, when pronounced ku, is a homophone for suffering (苦). See tetraphobia. The number 13 is sometimes considered unlucky, though this is a carryover from Western tradition. In contrast, numbers 7 and sometimes 8 are considered lucky in Japanese.^[2]

In modern Japanese, cardinal numbers are given the on readings except 4 and 7, which are called yon and nana respectively. Alternate readings are used in month names, day-of-month names, and fixed phrases. For instance, the decimal fraction 4.79 is always read yon-ten nana kyū, though April, July, and September are called shi-gatsu (4th month), shichi-gatsu (7th month), and ku-gatsu (9th month) respectively. The on readings are also used when shouting out headcounts (e.g. ichi-ni-san-shi). Intermediate numbers are made by combining these elements:

• Tens from 20 to 90 are "(digit)-jū" as in 二十 (ni-jū) to 九十 (kyū-jū).
• Hundreds from 200 to 900 are "(digit)-hyaku".
• Thousands from 2000 to 9000 are "(digit)-sen".

There are some phonetic modifications to larger numbers involving voicing or gemination of certain consonants, as typically occurs in Japanese (i.e. rendaku): e.g. roku "six" and hyaku "hundred" yield roppyaku "six hundred".

* This also applies to multiples of 10. Change ending -jū to -jutchō or -jukkei.
** This also applies to multiples of 100. Change ending -ku to -kkei.

In large numbers, elements are combined from largest to smallest, and zeros are implied.

Other types of numerals[]

Beyond the basic cardinals and ordinals, Japanese has other types of numerals.

Distributive numbers are formed regularly from a cardinal number, a counter word, and the suffix -zutsu (ずつ), as in hitori-zutsu (一人ずつ, one person at a time, one person each).

Powers of 10[]

Large numbers[]

Following Chinese tradition, large numbers are created by grouping digits into myriads (every 10,000) rather than the Western thousands (1,000):