I started learning Japanese not long ago and I'm quite confused about two numbers.

Seven and nine, I have learned that seven is shichi and that nine is ku.
But I also know that seven is nana, and nine is kyu, actually I cannot remember ever hearing anyone use shichi and ku.

So basically my questions are, why there is more then one word for those numbers in particular and when to use which form.


3 Answers 3


About pronunciations:

Shichi/Nana and Kyuu/Ku and Shi/Yon

Both are all correct, this is a matter of taste, but in some expressions you have to use one in particular.

Japanese will use either shichi or nana.

People usually use kyuu except in some words like kugatsu as said by Sqrtbottle.

Also Japanese would rather not use shi as it has the same pronunciation as the shi in Shinu which means death, but both are perfectly correct and are a matter of taste. I know several Japanese who use shi.

About the meaning of numbers:

It is wrong to say the Chinese root ones are more commonly used. This is just a different usage. Basically if you start learning Japanese you should start by learning:

いち に さん し/よん ご...

Those are mostly used for mathematics and calculations.

But for speech, there are a lot of different counting systems. (to count things) The most basic one is like this:

ひとつ ふたつ みっつ よっつ ...

You are supposed to use it for counting things, but this is not as simple as that. If you start learning, only knowing both is ok. But to understand daily Japanese you need to learn a lot of different counters:

いっぽん にほん さんぼん (counter for long stuff like bottles, straws etc ...)
いちまい にまい さんまい (counter for thin stuff like sheets of paper)
いっぱい にはい さんばい (counter for cups of drink)

There are a lot of those.

So basically, they all have their own usage. If you don't know the special counters it's ok, just use the basic version (ひとつ ふたつ...), your grammar will be correct. But using special counters is always better, it lets you build shorter sentences and will sound more Japanese.

Don't forget, you are not supposed to count stuff with いち に さん.

Let's do some examples:

いちたすいち : 1 plus 1

いっぱいちょうだい : give me one cup

As you can see in the second one, all you can see is the counter for cups and choudai, so implicitly you understand that we are talking about cups. One last example:

3まいたりない : literally means "I lack 3 thin objects", but depending on the context, you could be printing things in the office, people will understand it like: "I need 3 more sheets of paper to finish my print", this is how this sentence would be translated and how Japanese will understand it. Saying [紙]{かみ}がみっつ[足]{た}りない might be grammatically correct but it doesn't sound good.

  • 3
    "plus" is 足{た}す in Japanese. 1 + 1 would be read as "いち 足{た}す いち"
    – sqrtbottle
    May 12, 2015 at 21:48
  • 1
    both are used, of course 足たすis the correct version if you are doing mathematic seriously, but some people will say プラス in informal situations and in several other situations. When you start learning japanese it's a good point to understand that a lot of english words have been introduced in japanese with katakana and are used in some extent in japanese.
    – Sam
    May 12, 2015 at 22:05
  • 2
    いっぽん にっぽん? That's kind of cute, actually :D
    – dainichi
    May 13, 2015 at 3:24

The forms derive from two roots: Japanese ones and Chinese ones.

Japanese ones are 1 ひ、2 ふ、3 み、4 よ(ん)、5 い(つ)、6 む、7 なな、8 や、9 ここの、10 とお etc.
Chinese ones are 1 いち、2 に、3 さん、4 し、5 ご、6 ろく、7 しち、8 はち、9 きゅう (also く)、10 じゅう

Generally the Chinese ones are more common. They're used for counting objects with counters (if you know what these are), like animals and objects, and even just numbers on their own (like 1 + 1 = 2).

The Japanese ones are used in counting things with a ~つ suffix, which is the general counter for objects, and you also see them in some words like ひとり (one person) and ふたり (2 people), as well as in some of the days of the month, and in peoples' names.

Which is more common?

Japanese ones see much more limited usage, but people will use よん in place of し and なな in place of しち to make it clearer which they mean (as they sound similar). These two are mixed in with Chinese numbers in usage quite a lot.

Which to use needs to be done on more of a case-by-case basis depending on what you're talking about, but on the whole Chinese numbers (ichi, ni, san) are more commonly used.


Not that frequently used, and never on its own. You'll usually hear this one (irregularly) instead of きゅう when counting things (September is "kugatsu" rather than "kyuugatsu").


To use ku an shichi they are used in different situations one situation is time to say seven o'clock you would say shichi ji. ji indicates hour. It is important to learn all way of counting when learning the language so that if some one is using the alternate form you can pick up what they are saying. Examples ku ji, shichi ji (hours)

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