mittsu vs san - what's the difference and what are these two forms called?


I am trying to learn the numbers and I see there are two different
translations for the number 3 (and other numbers). When should I use one and
when should I use the other? Is there a name for the type of number that "san"
is and the type of number that "mittsu" is?




There are mainly two types of numbers used in Japanese:

  * native Japanese numbers (和語数詞 _wago sūshi_ )

> 1 ひと _hito_ , 2 ふた _futa_ , 3 み _mi_ , 4 よ _yo_ , 5 いつ _itsu_ , 6 む _mu_ , 7
> なな _nana_ , 8 や _ya_ , 9 ここの _kokono_ , 10 と _to_ , ...

  * Chinese-derived numbers (漢語数詞 _kango sūshi_ )

> 1 いち _ichi_ , 2 に _ni_ , 3 さん _san_ , 4 し _shi_ , 5 ご _go_ , 6 ろく _roku_ , 7
> しち _shichi_ , 8 はち _hachi_ , 9 きゅう _kyū_ , 10 じゅう _jū_ , ...

(Some counters may also take English-derived numbers (英語数詞 _eigo sūshi_ ) ワン
_wan_ "one", ツー _tsū_ "two", スリー _surī_ "three" in low numbers.)

**Caveat**. Depending on the counter word coming after it, these numbers may
slightly change.

* * *

### _mittsu_

The native みっつ _mittsu_ is of the form [number] + [counter word], where the
number is the native Japanese み _mi_ that goes with the counter word ～つ (a
generic counter for objects) and

> み + ～つ → み **っ** つ. (See the above caveat.)

### _san_

さん _san_ is of the form [number], where the number belongs to the Chinese-
derived counting system. It cannot be used to count anything (items, people,
...) by itself.

However, for counting by itself (e.g. during exercise, hide-and-seek, etc.)
the Chinese-derived numbers are used (sometimes しち is replaced by なな).

During counting, these are often _pronounced_ rhythmically

> イチ【HL】、 ニー【HL】、 サン【HL】、 シー【HL】、 ゴー【HL】、 ロク【HL】、 シチ【HL】、 ハチ【HL】、 キュウ【HHL】、
> ジュウ【HHL】

even though they are always _written_ as above.

