How Japanese Kanji Numbers Work (漢数字の仕組み)
Japanese uses two parallel number systems: Arabic numerals (1, 2, 3) for everyday use, and kanji numerals (一, 二, 三) for formal writing, classical texts, and certain official documents. The kanji number system uses place-value notation: 十 (10), 百 (100), 千 (1,000), and 万 (10,000) as place markers, combined with digit kanji. One important rule: 十, 百, and 千 do not take a leading 一 — you write 十 for 10, not 一十. However, 万 and above do take 一 — so 10,000 is 一万.
Japan groups large numbers in units of 10,000 (四桁区切り) rather than 1,000 as in English. This means 100,000 is 十万 (ten-man), 1,000,000 is 百万 (hundred-man), and 100,000,000 is 一億 (one-oku). This grouping is fundamental to reading prices, statistics, and financial figures in Japanese.
Daiji (大字) — Formal Kanji Numbers for Documents
Daiji (大字) are complex kanji variants used specifically in financial and legal documents to prevent fraud. Because standard kanji numbers like 一, 二, 三 can be altered easily (adding strokes to change the numeral), daiji uses more complex forms: 壱 (1), 弐 (2), 参 (3), 伍 (5), 拾 (10). You will find daiji on Japanese bank checks (小切手), promissory notes (約束手形), contracts, and some government forms. The converter above can output any number in daiji format.
For reading Japanese numbers aloud, see the reading column in the reference table below. Note that some numbers have two readings: 4 can be し or よん, and 7 can be しち or なな, depending on context. For converting Japanese text including kanji, use the romaji converter.