が (ga): The Subject Marker (and When to Use It)
What it means
が is the subject particle: it points at who does the action or what is being described. It also carries a job that English handles with stress or word order — it spotlights new or important information. When you answer a "who?" or "what?" question, the answer takes が. And a set of very common N5 patterns — existence, ability, and likes/wants — simply require が by rule.
ヤッタンが来ました。
ヤッタンが きました。
Yattan came.
が marks Yattan as the subject who did the action.
空が青いです。
そらが あおいです。
The sky is blue.
が presents the sky as new information being described.
猫がいます。
ねこが います。
There is a cat.
Existence verb いる takes が.
How to form it
There is nothing to conjugate — が attaches directly to the noun that is the subject. The trick is knowing which noun gets it.
| Situation | Pattern | Example |
|---|---|---|
| Subject of an action | Noun が + verb | ヤッタンが食べる |
| Answer to a question word | だれ／なに が… | だれが来た？ |
| Existence | Noun が ある／いる | 犬がいる |
| Ability | Noun が できる | 日本語ができる |
| Likes / skill / wanting | Noun が 好き／上手／ほしい | すしが好き |
Introducing new information
Use が when the subject is the new or surprising part of the sentence — especially when it answers a question word like だれ ("who") or なに ("what"). The question word itself takes が, and so does the answer.
だれが来ましたか。
だれが きましたか。
Who came?
Question word だれ takes が, never は.
ヤッタンが来ました。
ヤッタンが きました。
Yattan came.
The new answer also takes が.
どれがモチのかさですか。
どれが モチの かさですか。
Which one is Mochi's umbrella?
どれ asks 'which', so it takes が.
が with existence, ability, and feelings
Several everyday N5 patterns hard-wire が. With existence verbs ある (things) and いる (living beings), the thing that exists takes が. With できる ("can do"), the skill or task takes が. And with adjectives of liking, skill, and wanting — 好き, 上手, ほしい, and the 〜たい form — the object of the feeling takes が.
つくえの上に本があります。
つくえの うえに ほんが あります。
There is a book on the desk.
ある for non-living things → が.
ヤッタンは日本語が好きです。
ヤッタンは にほんごが すきです。
Yattan likes Japanese.
好き takes が for the liked thing. Yattan, the topic, takes は.
先生はピアノが上手です。
せんせいは ピアノが じょうずです。
The teacher is good at piano.
上手 (skilled) takes が.
モチは泳ぐことができます。
モチは およぐことが できます。
Mochi can swim.
できる (ability) takes が.
Wanting works the same way: a wanted thing takes が with 〜ほしい, and a wanted action takes が with 〜たい — ヤッタンの弟は水がほしい ("Yattan's brother wants water").
How が differs from は (at a glance)
Both can sit near the start of a sentence, but they do different jobs. は marks the topic ("as for…") and often points to known, background information. が marks the subject and spotlights new or specific information. Compare: 私は学生です ("As for me, I'm a student" — topic) versus 私が学生です ("I am the student" — answering "who is?").
A quick rule of thumb: if the noun answers a question word, or is brand-new to the conversation, lean toward が. If it's the known thing you're talking about, lean toward は. The difference is subtle and worth its own page — see the full breakdown in が vs は.
Common mistakes
- Using は after a question word. だれ, なに, どれ and friends take が, not は: だれが来ましたか (✓), not だれは来ましたか.
- Using を with 好き / 上手 / できる. These take が for their object: 日本語が好き (✓), not 日本語を好き.
- Forcing が when は fits better. For known, background subjects use は: ヤッタンは学生です ("Yattan is a student" — just stating a fact about a known character).
- Dropping が in existence sentences. The thing that exists needs が: 猫がいる (✓), not 猫いる in careful speech.
Quick recap
- が marks the subject — the doer or the thing being described.
- Use が to introduce new information and to answer question words (だれが, なにが).
- Existence (ある／いる), ability (できる), and feelings (好き・上手・ほしい・〜たい) take が.
- は = known topic; が = new subject. For the deep dive, see が vs は.
Your turn
Choose the correct particle: が or は.
Start the 5-question drill →Frequently asked questions
What does the particle が do?
が marks the grammatical subject — the person or thing doing the action or being described. It also spotlights new or important information, like the answer to a 'who?' or 'what?' question: だれが来ましたか → ヤッタンが来ました.
Why does 好き use が and not を?
In Japanese, 好き ('liked'), 上手 ('skilled'), and できる ('can do') treat their object as a subject of feeling or ability, so it takes が: 日本語が好き, ピアノが上手, 泳ぐことができる.
Which particle goes with ある and いる?
The thing that exists takes が: 本があります ('there is a book'), 猫がいます ('there is a cat'). ある is for things, いる for living beings.
When do I use が instead of は?
Use が for new information and for answers to question words (だれが, なにが). Use は for the known topic you're talking about. See the full comparison at /compare/wa-vs-ga.