Ko Counter (個) - The General Small Counter
The Japanese counter 個 (ko) is the Sino general-purpose fallback for small compact objects. Apples, eggs, balls, batteries, stones, candies. When you do not know the specific counter, ko is the safe choice. Gemination at 1, 6, 8 (or hachi-ko), 10.
Small, compact objects: apples, eggs, balls, batteries. The general fallback for objects.
| # | Kanji | Romaji | Notes | Audio |
|---|---|---|---|---|
| 1 | 一個 | ik-ko | gemination | |
| 2 | 二個 | ni-ko | ||
| 3 | 三個 | san-ko | ||
| 4 | 四個 | yon-ko | ||
| 5 | 五個 | go-ko | ||
| 6 | 六個 | rok-ko | gemination | |
| 7 | 七個 | nana-ko | ||
| 8 | 八個 | hak-ko / hachi-ko | ||
| 9 | 九個 | kyū-ko | ||
| 10 | 十個 | juk-ko / jik-ko |
What counts as a small compact object
- Fruit / vegetables: apples (りんご ringo), oranges (みかん mikan), eggs (卵 tamago), potatoes, tomatoes.
- Round / compact: balls (ボール booru), batteries (電池 denchi), candies (キャンディ kyandi), nuts.
- Stones / objects: stones (石 ishi), rocks (岩 iwa), gemstones, small souvenirs.
- Bags / luggage: small bags, suitcases, pieces of luggage (also takes 個 in airline counting).
- Abstract units: ideas, tasks, items on a list, often takes 個 in casual speech.
Ko versus tsu
Ko (Sino): works 1 to infinity. Regular gemination pattern. The reliable Sino fallback.
Tsu (native): works 1 to 10 only (hitotsu, futatsu, mittsu... to). Older, slightly more colloquial. Used for objects 1 to 10 when the specific counter is unknown.
Interchangeable: mittsu no ringo and san-ko no ringo both mean “three apples”. Casual speech tolerates either.
Sound-change pattern
Gemination at 1 (ik-ko), 6 (rok-ko), 10 (juk-ko / jik-ko). At 8, both hak-ko (with gemination) and hachi-ko (regular Sino) are heard; NHK and Genki list both. No rendaku at san: it is san-ko, not san-go.
Frequently asked questions
What is the difference between ko and tsu?
Both are general counters for objects. Ko (個) is Sino-Japanese, takes regular Sino numbers (ik-ko, ni-ko, san-ko...), and works for any number. Tsu (〜つ) is native (Yamato), takes the older readings (hitotsu, futatsu...), and works only 1 to 10. In casual speech they are often interchangeable for small objects under 10; above 10 only ko works.
Can I use ko for everything?
For small compact objects: yes, broadly. Ko is the safe Sino fallback. Native speakers will accept ko for apples, eggs, balls, batteries, stones, candies, small souvenirs. For long objects (use hon), flat objects (use mai), animals (use hiki / to / wa), and people (use nin), ko is the wrong choice and sounds off.
Why is san-ko spelt with k and not g?
Ko does not undergo rendaku at san. Unlike 本 (san-bon) and 匹 (san-biki) which voice to /b/, the /k/ of ko remains stable. The gemination at 1, 6, 10 (ik-ko, rok-ko, juk-ko) is independent of the rendaku pattern.
What about hak-ko versus hachi-ko at 8?
Both are heard. Hak-ko follows the regular gemination pattern (like ik-ko, rok-ko, juk-ko). Hachi-ko keeps the Sino reading clean. NHK Pronunciation Dictionary lists both as standard; Genki I teaches hak-ko as the default.
Continue: counters hub · native tsu · long objects (hon).