Japanese numerals

The system of Japanese numerals is the system of number names used in the Japanese language. The Japanese numerals in writing are entirely based on the Chinese numerals and the grouping of large numbers follow the Chinese tradition of grouping by 10,000. Two sets of pronunciations for the numerals exist in Japanese: one is based on Sino-Japanese (on'yomi) readings of the Chinese characters and the other is based on the Japanese yamato kotoba (native words, kun'yomi readings).

Basic numbering in Japanese

There are two ways of writing the numbers in Japanese, in Hindu-Arabic numerals (1, 2, 3) or in Chinese numerals (一, 二, 三). The Hindu-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 and a native Japanese reading used for ordinal numbers, though there are some exceptions (listed below) in which the Japanese version is preferred for both.