The first two pages in this group chose は or が by information age and by exhaustive focus. This one — the most advanced of the three — chooses by scope: how far the particle's phrase reaches over negation, questions, and clause boundaries. The key structural fact is that は is a main-clause, discourse-level marker that floats above the predicate, while が is a case particle welded inside the clause. That single asymmetry decides three things that trip up even upper-intermediate learners: what a negation actually denies, where you're allowed to put は at all, and what a question is really asking. For the ground-level system see the particle page; this page is the scope specialist.
は escapes negation; が (and を) stay inside it
Because は sits above the clause, a negation below it can't reach up and cancel it. The result: は narrows what is actually being denied — it pulls its own phrase out of the negation's scope, leaving a contrastive "at least this one isn't…" reading.
私はコーヒーを飲まない。
watashi wa kōhī o nomanai
I don't drink coffee. (plain, whole-predicate negation)
私はコーヒーは飲まない。
watashi wa kōhī wa nomanai
Coffee, I don't drink — other things, maybe I do.
With を, コーヒー sits inside the negation: "I don't [drink coffee]," a flat fact. Swap that を for a second は and コーヒー jumps outside the negation: now you're denying coffee specifically, with a live implication that other drinks are fine. (Yes — you can have two は in one clause: 私は is the topic, コーヒーは is contrastive. That's normal.) The same contrastive machinery lets you set two things against each other:
肉は食べないけど、魚は食べるよ。
niku wa tabenai kedo, sakana wa taberu yo
I don't eat meat, but I do eat fish.
This scope behaviour becomes genuinely meaning-changing with quantifiers. Watch は turn total negation into partial negation:
宿題は全部終わらなかった。
shukudai wa zenbu owaranakatta
I couldn't finish the homework at all / any of it.
宿題は全部は終わらなかった。
shukudai wa zenbu wa owaranakatta
I didn't finish all of the homework. (I did some, just not all.)
Attaching は to 全部 ("all") lifts all out of the negation's reach. Instead of "not [finish]" you get "not [all]" — some got done, the whole didn't. This は-for-partial-negation is invisible to anyone who thinks は is just a subject marker, and it is a favourite on the N2 exam.
In a subordinate clause, the subject must be が (or の) — never は
Because は marks what the whole sentence is about, it cannot live inside a relative clause, a noun-modifying clause, or a complement clause — a subordinate clause is not "what the sentence is about." So the subject down there is forced onto が (or, in noun-modifying clauses, optionally の; see the が vs の in relative clauses page).
私が読んだ本は、とても面白かった。
watashi ga yonda hon wa, totemo omoshirokatta
The book I read was really interesting.
Inside the relative clause 私が読んだ ("that I read"), the subject must be 私が; ×私は読んだ本 is ungrammatical as a relative clause, because は would try to make "I" the topic of the whole sentence, and the whole sentence is about the book (本は). The ban holds in complement clauses too — the が-marked subject of an embedded "that…" clause can't become は:
彼が結婚したことを、まだ知らなかった。
kare ga kekkon shita koto o, mada shiranakatta
I didn't know (that) he had gotten married.
雨が降っているかどうか、分からない。
ame ga futte iru ka dō ka, wakaranai
I don't know whether it's raining.
In 彼が結婚したこと and 雨が降っているかどうか, the embedded subjects (彼, 雨) sit inside their clauses, so they take が. The moment you promote one of them to the topic of the whole utterance, は appears — and it appears on the main clause, not the embedded one.
In questions, が seeks a value; は presupposes the referent
Scope shows up in questions too. A wh-question needs to identify an unknown value, so its subject is が — you can't topicalize the thing you're asking about (this is why 誰が / 何が are fixed, covered on the exhaustive-focus page). A yes-no question, by contrast, takes は when you're asking about an already-known referent — "as for X, is it the case that…?"
誰が来ますか。
dare ga kimasu ka
Who's coming? (asking for the unknown value)
田中さんは来ますか。
Tanaka-san wa kimasu ka
Is Tanaka coming? (as for Tanaka — will he come?)
田中さんは来ますか presupposes Tanaka (a known person) and asks whether "coming" holds of him — the question's focus is the predicate. Switch to 田中さんが来ますか and the focus moves onto the subject: "is it Tanaka who's coming?" — a question about which person, appropriate when you're checking an identity rather than a yes/no about a known individual. The particle tells your listener where the real question mark is pointing.
Decision procedure
| Ask, in order… | Then use |
|---|---|
| Is the subject inside a relative / こと / と / かどうか clause? | が (or の) — は is banned there |
| Do I want to contrast, or spare one phrase from the negation ("not all", "coffee at least")? | は on that exact phrase |
| Is it a wh-question seeking an unknown value? | が |
| Is it a yes-no question about an already-known referent? | は |
| Plain main-clause topic, whole-predicate statement? | は on the topic, が on a fresh subject |
Common mistakes
❌ 私は読んだ本はとても面白かった。
Incorrect — the relative-clause subject can't be a topic; inside 〜読んだ本 it must be 私が. は belongs only to the whole sentence's topic (本は).
✅ 私が読んだ本はとても面白かった。
watashi ga yonda hon wa totemo omoshirokatta
The book I read was really interesting.
❌ 田中さんは来たことを知らなかった。
Wrong for 'I didn't know that Tanaka came' — は reads as the main topic ('as for Tanaka, [I] didn't know [someone] came'). The embedded subject needs が.
✅ 田中さんが来たことを知らなかった。
Tanaka-san ga kita koto o shiranakatta
I didn't know that Tanaka had come.
❌ 宿題は全部終わらなかった。
Says the opposite of what's intended when you mean 'not all of it' — without は on 全部, this is whole-negation ('I got none of it done'). To mean 'not all', は must sit on 全部.
✅ 宿題は全部は終わらなかった。
shukudai wa zenbu wa owaranakatta
I didn't finish all of the homework.
❌ コーヒーを飲まない。
Loses the contrast when you mean 'coffee, at least, I don't drink (other things I might)' — を keeps coffee inside the plain negation. Put は on コーヒー to carry the contrast.
✅ コーヒーは飲まない。
kōhī wa nomanai
Coffee, I don't drink.
The single thread: decide by where each particle's phrase sits relative to the clause and the negation. は floats on top — it escapes negation and is exiled from subordinate clauses; が lives inside — it's forced in embedded clauses and stays within a negation's reach. Get the scope right and the meaning follows.
Key takeaways
- は floats above the clause; が sits inside it. That asymmetry drives every rule here.
- は escapes negation → contrastive readings (コーヒーは飲まない) and partial negation (全部は食べない = "not all").
- は is banned in relative / こと / と / かどうか clauses — the embedded subject must be が (or の).
- Wh-questions take が (unknown value); yes-no questions about a known referent take は (田中さんは来ますか).
- When stuck at N2, stop thinking "topic vs subject" and think scope: where does this particle's phrase reach?
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Start learning Japanese→Related Topics
- は vs が: Exhaustive Listing & FocusN3 — The it-cleft test for は vs が — が can spotlight one referent as the sole satisfier of the predicate ('it's X, and only X'), while は presents it neutrally, plus why question words are locked to が.
- は vs が: New vs Known InformationN4 — A fast decision procedure for the は/が choice based on one question — does the listener already have this information? — plus the 'track the age, not the role' rule that resolves most sentences.
- の Replacing が in Modifying ClausesN4 — Inside a noun-modifying (relative) clause, the subject が can be swapped for の — 私が作ったケーキ = 私の作ったケーキ, 髪の長い人 — and why that の is a signal you're inside a modifier.
- は vs が: Topic vs SubjectN5 — The core は/が contrast — known/framed information takes は, new/identifying information takes が — with the story-opening pattern, wh-questions, negation scope, and the 象は鼻が長い double-subject sentence.