Every learner reaches the same wall around week three: the textbook says は marks the topic and が marks the subject, you nod, and then the next exercise asks you to fill the blank in 誰___来ましたか and you guess wrong. Again. The truth is that は vs が is not really a grammar question — it is a question about what information you are presenting and what the listener already knows. Once you see it that way, the wall falls down.
1. The Information-Flow Model
Japanese sentences are built around a flow of known → new. は marks the known half (the topic). が marks new identity. The verb at the end carries the meaning either way.
- 「私は学生です。」 As for me (you already know who I am), I am a student. — new info: 学生.
- 「私が学生です。」 The student is me. — new info: 私.
Same words, opposite information weight. Native speakers feel this difference the moment the particle leaves your mouth.
2. The Five Forced-が Patterns
Five environments lock you into が. If you pick up nothing else from this article, learn these five.
| Pattern | Example | Why が |
|---|---|---|
| Wh-question subject | 誰が来ましたか。 | The questioned noun is the new info |
| First-time introduction | あ、ねこがいる！ | The cat is brand-new in the conversation |
| Existence / possession | かばんの中に本があります。 | ある/いる prefer が |
| Ability / preference | 日本語がわかります。 | わかる, できる, 好き, 嫌い take が |
| Subordinate clause subject | 雨が降る日は出かけません。 | Subordinate clauses keep their own subject |
3. The Three Forced-は Patterns
- Contrast: 「肉は食べますが、魚は食べません。」 — implicit comparison.
- General truth about a known topic: 「象は鼻が長い。」 — “Speaking of elephants, the nose is long.”
- Negative comments about a known topic: 「彼は来ませんでした。」 — pre-supposes you both know who 彼 is.
4. The Question / Answer Echo Test
The single fastest way to choose between は and が in real time: imagine the question that produces your sentence. The new information in the answer takes が; everything else takes は.
Q: 誰が学生ですか？ → A: 私が学生です。 (new = 私)
Q: あなたは何ですか？ → A: 私は学生です。 (new = 学生)
5. The Big Trap: Translation Brain
English has no topic particle. So learners default to が because it “feels like the subject of an English sentence.” That is why beginner Japanese sounds slightly off even when every word is correct. Train yourself to ask “is this noun already on the table?” before reaching for が. If yes, は wins.
6. Embedded Clauses Always Take が
Inside a relative or subordinate clause, the subject takes が, not は. This is a non-negotiable structural rule.
「父が作った料理はおいしかった。」
The food my father made was delicious.
父は作った here would feel broken to a native — the topic of the whole sentence is 料理, not 父.
7. The N5 Discrimination Drill
Reading the rule does not build the reflex. The reflex is built by repeated forced choice under SRS. Build a deck like this:
- Take 20 sentences using either は or が.
- Cloze the particle out.
- Tag each card with the rule it tests (intro, contrast, embedded, etc.).
- When you fail one, write your reason on the back. Failed cards return automatically.
This is exactly the workflow Kanjijo’s N5 grammar deck uses, with the added bonus that the same sentence may appear twice — once requiring は and once requiring が — so your brain learns the discrimination, not the surface form.
The Quick Decision Tree
- Is the noun in question already known to your listener? → は
- Is the noun the answer to a wh-question, or brand-new in the scene? → が
- Is the verb ある, いる, わかる, できる, 好き, 嫌い? → が
- Are you contrasting two things? → は for both
- Is the subject inside a relative clause? → が
Drill は vs が Inside Kanjijo
Kanjijo’s N5 grammar deck includes 80+ pattern cards with exclusive mnemonics, bilingual examples and OCR scanning so you can capture から, ので, は or が the moment you spot one in a real sign or manga panel.
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Frequently Asked Questions
は marks the topic — what the sentence is about — and is usually old information. が marks the grammatical subject and is usually the new information itself. は zooms out; が zooms in.
Sometimes, but the focus shifts. With は the new info comes after the verb; with が the noun itself is the new info. Native speakers feel the shift instantly.
With wh-question subjects, first-time introductions, ある/いる/わかる/できる, and inside subordinate clauses.
In contrast, in negative comments about a known topic, and in general statements about a topic.
Cloze cards in an SRS such as Kanjijo, where the same sentence appears in two forms — one requiring は, one requiring が — so the discrimination is what the brain learns.