Kanji numerals vs. Arabic numerals
Numerals in Japanese can be written in both kanji and Arabic numbers (theoretically, in kana as well, but that's not common at all). For example, "one" can be both "一" and "１".
How do you choose whether it's best to use kanji or Arabic numbers when you're writing?
There are no strict rules, but there are some pointers you can follow:
- The date is typically written in Arabic numerals, unless it's a very formal document. (e.g. ２００７年１１月１３日)
- The time is also usually written in Arabic numerals. (e.g. １０時３０分)
- When counting (for example: 一人, 二人, 三人...) either can be used, but you should be consistent. Don't switch back and forth between kanji and Arabic numbers.
- When writing vertically, kanji are usually used.
In general, kanji give a more "official" look to the text. Happy counting!