は or が: topic or subject
A は ～（what you say about it）／A が ～（who? what?）
は = known topic, the information comes after it. が = new subject, the subject itself is the information. Question word, something you notice, すき／ある／わかる: が.
In short
は presents the topic: something already known that you're going to say something about. が marks the subject when it is the new information: after a question word, for something you notice, and with ある・いる, すき, ほしい, わかる.
- だれが 来ましたか。——田中さんが 来ました。dare ga kimashita ka. tanaka-san ga kimashitaWho came? — Mr Tanaka did.
- 田中さんは 先生です。tanaka-san wa sensei desuMr Tanaka is a teacher.
- あ、ねこが いますよ。a, neko ga imasu yoOh, there's a cat!
The basics
は and が can both become the subject of an English sentence, but they don't say the same thing. は presents the topic: what you're talking about, already known, and you're going to say something about it. が marks the subject as new information: it's the part of the sentence that matters.
A good rule of thumb: in “A は B”, the important information is B. In “A が B”, it's A. English often does the same job with stress: “TANAKA is the teacher.”
- 田中さんは 先生です。tanaka-san wa sensei desuMr Tanaka is a teacher. (we're talking about Tanaka)
- 田中さんが 先生です。tanaka-san ga sensei desuMr Tanaka is the teacher. (answer to “who is the teacher?”)
When が is required
At N5, four situations call for が:
| Situation | Example |
|---|---|
| after a question word used as the subject | だれが 来ましたか。 |
| in the answer to that question | 田中さんが 来ました。 |
| for something you notice or see | あ、雨が ふって います。 |
| with ある・いる, すき, ほしい, わかる, じょうず | ねこが います／すしが すきです |
When は is natural
は is used for a known topic (I, you, something already mentioned), for definitions and general truths, and to contrast two things.
- わたしは 学生です。watashi wa gakusei desuI'm a student.
- にくは 食べますが、魚は 食べません。niku wa tabemasu ga, sakana wa tabemasenMeat, I eat; fish, I don't.
Both in the same sentence
With すき, ほしい or あります, you often find は for the person and が for the thing: わたしは すしが すきです. Each has its own job: the topic (me) and what is liked (sushi).
- ぞうは はなが ながいです。zō wa hana ga nagai desuElephants have long trunks. (word for word: as for elephants / the trunk / is long)
Common mistakes
- Writing だれは: a question word used as the subject always takes が.
- Answering with は to a question with が: to だれが 来ましたか, answer 田中さんが 来ました.
- Thinking が is “more correct”: both are correct, they just put the emphasis in different places.
5 exercises on this point
Particles to choose, sentences to put back in order, translations: marked straight away, then reviewed at the right time. This JLPT N5 point is on the Shinjuku Line (The city) of the Tokyo subway.