If you are learning from GENKI, you may have noticed something: the textbook uses both は and が from Lesson 1, but it does not stop to explain the difference between them. Lesson 3 is a good time to look at it, because you can now make real sentences with verbs.
Here is a question to start. Why is the second sentence wrong?
○ だれが来ますか。
Who is coming?
× だれは来ますか。
By the end of this guide, you will know the answer. We will use four simple points. All example sentences use words from GENKI Lessons 1–3 (plus a few helper words). Furigana is added to every kanji.
In this article: は = red, が = teal.
The basic idea
が marks the subject: who or what does the action, or is something.
は marks the topic: what you are talking about. It means “as for ~” or “speaking of ~”. The speaker usually thinks the listener already knows the topic. After は, you say the new or important information.
| Particle | Role | Where is the important information? |
|---|---|---|
| は | Topic (“as for ~”) | After it: 私は学生です。 As for me, I am a student. |
| が | Subject (“it is this one”) | Before it: 私が学生です。 I am the student. (Not someone else.) |
Point 1: Do both people already know it?
Use は for information that is already known (old information). Use が for information that is new to the listener (new information).
A たけしさんは学生ですか。
Is Takeshi a student?
B はい、たけしさんは学生です。
Yes, Takeshi is a student.
Both people know Takeshi. He is the topic, so we use は.
A だれが学生ですか。
Who is a student?
B たけしさんが学生です。
Takeshi is the student.
Person A does not know who the student is. The answer “Takeshi” is new information, so we use が.
| Situation | Particle | Example |
|---|---|---|
| Names, “the teacher”, things already in the conversation | は | 先生は毎日来ます。 The teacher comes every day. |
| Something or someone new in the conversation | が | 友だちが来ます。 A friend is coming. |
The folktale pattern
Japanese folktales show this clearly. First: 昔々、おじいさんが住んでいました。 (Once upon a time, an old man lived there.) Next: おじいさんはとてもやさしい人でした。 (The old man was very kind.) The old man was new, then he became known. It is like “a” and “the” in English. This is only a rough guide, but it helps. (The past tense is new, so just look at the particles.)
Why “だれは来ますか” is wrong
だれ (who) and 何 (what) ask for information you do not know. A word like that can never be “already known”, so it cannot be the topic. When だれ or 何 is the subject, always use が.
Note: あの人はだれですか。 (Who is that person?) is fine. Here だれ is not the subject. あの人 is the known topic.
Point 2: Are you describing what you see, or giving a judgement?
Use が when you report something you see or notice, just as it is. This is called a phenomenon sentence. Use は when you talk about something and say what you know or think about it. This is called a judgement sentence.
| Type | は | が |
|---|---|---|
| Sentence type | Judgement (subjective) | Phenomenon (objective) |
| Feeling | “Let me tell you about ~” | “Look! ~ is happening!” |
| Example | 友だちは来ます。 (About my friend:) He is coming. | あ、友だちが来ます！ Oh, my friend is coming! |
You already know a judgement sentence: the basic XはYです from Lesson 1. When you say あの人は先生です, you are judging “that person” and saying what he or she is.
Point 3: How far does the particle reach?
The topic with は reaches to the end of the sentence, and it can even continue into the next sentence. You do not need to say it again.
私は毎朝 コーヒーを飲みます。そして、新聞も読みます。
I drink coffee every morning. And I also read the newspaper.
Here 私は is the topic of both sentences. That is why we understand that I read the newspaper too.
Advanced: が inside a small clause
○ 私が読んだ本は「雪国」です。
The book I read is Snow Country.
× 私は読んだ本は「雪国」です。
The topic は does not usually go inside a small clause like “(that) I read”. Inside the small clause, the subject is marked with が. The topic of the whole sentence is 本は. You will study this pattern later in GENKI. (Contrast は can still appear inside a clause, but that is for a later level.)
Point 4: Are you comparing, or saying “this one!”?
は can mean contrast
When you put two things side by side, は shows the difference.
コーヒーは飲みます。でも、お茶は飲みません。
I drink coffee, but I don’t drink tea.
Sometimes the contrast is only a hint. Look for these clues. They are tendencies, not strict rules.
| Clue | Example | Hidden feeling |
|---|---|---|
| Two things side by side | 肉は食べます。魚は食べません。 | meat: yes / fish: no |
| Negative sentence | お茶は飲みません。 | (I drink other things.) |
| Said with stress | 日本語は話します。 | (I speak Japanese, but maybe not other languages.) |
| Two は in one sentence | 私は今日は勉強しません。 | The first は is the topic. The second は contrasts: (today, not other days). |
が can mean “this one, and no other”
When が is used in an answer, it points to the answer: “this one!”. This is called exclusion.
A だれが来ますか。
Who is coming?
B 田中さんが来ます。
Tanaka is coming. (Tanaka, not the others.)
If B says 田中さんは来ます, B is only talking about Tanaka. Maybe other people will come, maybe not.
What happens to the other particles?
When you use は for a topic or for contrast, it works together with other particles in a special way.
| Particle | What happens with は | Example |
|---|---|---|
| を / が | Disappears. は takes its place. | コーヒーを飲みます → コーヒーは飲みます × コーヒーをは |
| で / と / に (time, person) | Stays. は is added after it. | ここでは食べません。 I don’t eat here. (Maybe elsewhere.) 友だちとは会いません。 I don’t meet with a friend. (Maybe with someone else.) |
Cheat sheet
| Point | は (topic) | が (subject) |
|---|---|---|
| 1. Information | Already known | New |
| 2. Sentence type | Judgement: talk about the topic | Phenomenon: what you see |
| 3. Reach | To the end of the sentence, and into the next | The subject of a small clause |
| 4. Meaning | Contrast (comparing) | Exclusion (“this one!”) |
Common mistakes
| Mistake | Correct | Why |
|---|---|---|
| × だれは来ますか。 | ○ だれが来ますか。 | A question word as the subject takes が. |
| × コーヒーをは飲みます。 | ○ コーヒーは飲みます。 | を disappears before は. |
| × あ、先生は来ます！ | ○ あ、先生が来ます！ | You report what you see: が. |
| × あの人がだれですか。 | ○ あの人はだれですか。 | “That person” is the known topic. |
Quick quiz
Fill in は or が. Click each question to see the answer.
1. A：たけしさん（ ）学生ですか。 B：はい、たけしさん（ ）学生です。
は / は. Takeshi is already the topic.
2. あ、友だち（ ）来ます！
が. You report what you see.
3. A：だれ（ ）来ますか。 B：田中さん（ ）来ます。
が / が. A question word as the subject takes が, and the answer is “this one!”.
4. コーヒー（ ）飲みます。でも、お茶（ ）飲みません。
は / は. You compare two things.
5. 私（ ）毎朝 コーヒーを飲みます。そして、新聞も読みます。
は. The topic “I” continues into the next sentence.
Free worksheet
Want more practice? Download the printable worksheet. It has fill-in questions, a sentence-choice section, a matching section, and an answer key.
