Japanese counters: the part of numbers that catches everyone

In Japanese you cannot count things without saying what kind of thing you are counting. The counter word changes with the object, and often the number changes shape with the counter.

This is a genuine difficulty and it shows up in exams constantly, because counters are exactly the kind of small precise detail that a listening or reading question can turn on.

The ones you actually need

Counter	For	1, 2, 3
〜つ	General things (1–9)	ひとつ, ふたつ, みっつ
〜人	People	ひとり, ふたり, さんにん
〜個	Small objects	いっこ, にこ, さんこ
〜本	Long thin things	いっぽん, にほん, さんぼん
〜枚	Flat things	いちまい, にまい, さんまい
〜台	Machines, vehicles	いちだい, にだい, さんだい
〜冊	Books	いっさつ, にさつ, さんさつ
〜杯	Cupfuls	いっぱい, にはい, さんばい
〜回	Times, occurrences	いっかい, にかい, さんかい
〜時間	Hours (duration)	いちじかん, にじかん
〜分	Minutes	いっぷん, にふん, さんぷん

The irregularities are the point

Notice what happens to the numbers. This is where the difficulty actually lives.

People are the worst offender and the most common: ひとり and ふたり are completely irregular, then it becomes regular from three — さんにん, よにん, ごにん.

Sound changes affect 一, 三, 六, 八 and 十 with many counters: いっぽん not いちほん, さんぼん not さんほん, いっぷん not いちふん.

These are not learnable from a rule. They are learned by saying them aloud, repeatedly, until the wrong version sounds wrong.

Why exams love them

Counters are short, unstressed and decisive. A listening clip says さんぼん and the question asks how many; a candidate who did not catch the counter has nothing. A reading question asks how many people, and the text says ふたり.

They are also ideal for wrong answers, because plausible alternatives are trivially easy to construct.

The practical minimum

If you are preparing for JFT-Basic and short of time, prioritise in this order:

1. People (〜人) — including ひとり and ふたり
2. Time: 〜時, 〜分, 〜時間, and the days and months
3. General things (〜つ) — the universal fallback
4. Money (〜円)
5. Times/occurrences (〜回)

Those five cover most of what the exam asks about. See how many words you need.

The escape hatch

〜つ works for a great many things when you do not know the right counter, up to nine. It is not always ideal, and it is always better than stopping.

Beyond nine, the plain number often serves. Japanese speakers will understand you. Precision here is worth points on an exam and very little in a conversation.

How to learn them

Aloud, in phrases you would use. ビールを さんぼん ください. きっぷを にまい おねがいします. Not as a grid.

With the sound changes drilled specifically. いっぽん, さんぼん, ろっぽん. These have to become automatic because the exam plays audio once.

In your spaced repetition, as whole phrases rather than as isolated counters. See spaced repetition for Japanese.

And then test whether it worked under time pressure — our free practice test includes listening items where a counter decides the answer.