は vs が主題と主語
は marks the topic (what the sentence is about). が marks the subject (who or what performs the action, or identifies new information). This distinction does not exist in English, which is why は vs が is the single most confusing point in Japanese grammar. These 7 rules will give you a reliable framework.
は marks the topic (what the sentence is about). が marks the subject (who or what performs the action, or identifies new information). This distinction does not exist in English, which is why は vs が is the single most confusing point in Japanese grammar. These 7 rules will give you a reliable framework.
The core difference: topic vs subject
Think of は as a spotlight: it says "As for X, let me tell you something." The information after は is the comment about X. が, on the other hand, identifies X itself — it answers "who?" or "what?" When someone asks 誰が来ましたか (Who came?), the answer uses が: 田中さんが来ました (Tanaka came). が points at Tanaka as the new information. If the question were 田中さんは？(What about Tanaka?), は marks Tanaka as already-known, and the answer provides new info: 田中さんはもう帰りました (Tanaka already left).
Rule 1: は for known information, が for new information
When you introduce something for the first time, use が. When you comment on something already established, use は. Imagine a story: むかしむかし、おじいさんが住んでいました。おじいさんは毎日山へ行きました。 (Once upon a time, an old man lived [が = introducing him for the first time]. The old man [は = now we know about him] went to the mountain every day.) This is the most fundamental rule.
Rule 2: が after question words (誰, 何, どこ, etc.)
Question words always take が, never は. 誰が作りましたか (Who made it?), 何が起きたんですか (What happened?), どこが痛いですか (Where does it hurt?). The answer to a が-question also uses が: 誰が来た？→ 山田さんが来た。This is because the question word represents unknown/new information, which is が’s domain.
Rule 3: が with existence verbs (いる, ある)
When stating that something exists or is present, use が: 冷蔵庫にビールがある (There is beer in the fridge). 公園に子供がいる (There are children in the park). The thing that exists is new information being presented. However, if the item is already the topic, は is fine: ビールはどこにありますか (Where is the beer? — beer is already known/topicalized).
Rule 4: が in subordinate clauses
Inside relative clauses, noun clauses, and conditional clauses, the subject is marked with が, not は. 私が作ったケーキ (the cake that I made), 彼が来るまで待ちましょう (let’s wait until he comes), 雨が降ったら中止です (if it rains, we’ll cancel). は cannot appear inside these subordinate clauses because は marks the overall topic of the sentence, not a clause-internal subject.
Rule 5: は for contrast
は creates an implicit contrast: 肉は食べるけど、魚は食べない (I eat meat, but I don’t eat fish). Both items get は because they’re being contrasted. Even a single は can imply contrast: 今日は暇です can mean "Today (unlike other days) I’m free." This contrastive use is extremely common and often overlooked by learners.
Rule 6: が with adjectives of desire and ability
Certain predicates take が for the object instead of を. The big three: ～が好きです (like), ～がほしいです (want), ～が分かります (understand). Also: ～ができる (can do), ～が上手 (skilled at), ～が見える/聞こえる (can see/hear). 日本語が分かります (I understand Japanese). コーヒーが好きです (I like coffee). Using を with these is a common foreigner mistake.
Rule 7: は cannot mark an exhaustive list
When you’re specifically identifying the only one(s), use が. この中で誰が一番背が高いですか (Among these, who is the tallest?) — トムが一番背が高いです (Tom is the tallest). Using は here would merely topicalize Tom. が exhaustively identifies him as the answer.
Double が structures
Some sentences need two が. The pattern is: [X]が[Y]が[predicate]. 私は頭が痛い (My head hurts — I as topic, head as subject of 痛い). 象は鼻が長い (Elephants have long noses — elephant as topic, nose as subject). These are not errors; the first noun is often topicalized with は while the second takes が.
Why this works
Japanese allows a topic (は) and a subject (が) to coexist. The topic sets the frame, and が marks the specific subject within that frame. 日本は桜が有名です (As for Japan, cherry blossoms are famous). This "double-subject" structure has no English equivalent and trips up every learner.
は vs が — side-by-side comparison
| Situation | Use は | Use が |
|---|---|---|
| Self-introduction | 私はジョンです (I'm John — general intro) | 私がジョンです (I'm the one who is John — identifying) |
| Describing weather | 今日は暑い (Today is hot — topic/contrast) | 雨が降っている (It's raining — subject of action) |
| Answering "who?" | — | 田中さんが来ました (Tanaka came) |
| Contrasting | 肉は好きだけど魚は嫌い | — |
| Inside relative clause | — | 私が書いた本 (the book I wrote) |
| Existence (ある/いる) | ビールはどこ？(Where's the beer?) | ビールがある (There's beer) |
| Desire/ability | — | 日本語が分かる, 寿司が好き |
Example sentences
田中さんはエンジニアです。
Tanaka-san wa enjinia desu.
Tanaka is an engineer.
は — introducing a fact about already-known Tanaka
誰が窓を割ったんですか。
Dare ga mado o wattan desu ka.
Who broke the window?
が — question word always takes が
犯人が分かりました。
Hannin ga wakarimashita.
The culprit has been identified.
が — new information being revealed
日本は物価が高い。
Nihon wa bukka ga takai.
Prices are high in Japan.
は topic + が subject (double-subject)
彼女が作ったケーキはおいしかった。
Kanojo ga tsukutta keeki wa oishikatta.
The cake she made was delicious.
が inside relative clause, は for main topic
肉は食べますが、魚は食べません。
Niku wa tabemasu ga, sakana wa tabemasen.
I eat meat, but I don't eat fish.
は for contrast (twice)
水が飲みたい。
Mizu ga nomitai.
I want to drink water.
が with ～たい (desire)
Common mistakes
誰は来ましたか。
誰が来ましたか。
Question words (誰, 何, どこ, etc.) always require が, never は. Question words are new/unknown information by definition.
日本語は分かりますか。(in most contexts)
日本語が分かりますか。
分かる takes が for what is understood. Using は is possible only when contrasting (日本語は分かるけど、中国語は…).
私は作ったケーキ (as relative clause)
私が作ったケーキ
Inside a relative clause modifying a noun, the subject must be marked with が, not は.
箱の中にりんごはあります。(to mean "there is an apple")
箱の中にりんごがあります。
When introducing the existence of something, use が. Using は would mean "As for the apple (which we already know about), it's in the box."
Frequently asked questions
Can I just always use は to be safe?
No. Using は where が is required changes the meaning or sounds unnatural. After question words, in relative clauses, with existence verbs introducing something new, and with adjectives like 好き/分かる, you must use が. However, in casual conversation, natives sometimes drop particles entirely, which is a different pattern.
Is は a particle? It's written with the hiragana は (ha) but pronounced "wa."
Yes, は is a particle. In modern Japanese, the topic marker は is always pronounced "wa" even though it uses the hiragana は (ha). This is a historical spelling convention. The particle を is similarly written with を but often pronounced "o" in standard speech.
How do native speakers decide between は and が so quickly?
Native speakers don't think about rules — they rely on context and intuition built from thousands of hours of input. As a learner, start with the 7 rules, but the real mastery comes from massive reading and listening. Over time, wrong choices will "sound off" to you, just as incorrect English articles ("a" vs "the") sound off to English natives.
What about は and が both appearing in the same sentence?
This is completely normal and very common. は sets the topic, and が marks the subject within the comment: 象は鼻が長い (As for elephants, the nose is long). 私はコーヒーが好きです (As for me, coffee is liked). The topic frame (は) and the subject (が) serve different grammatical roles.
Which particle goes after 誰 in a question?