Introduction
For many learners of Japanese, the difference between は (wa) and が (ga) is one of the most confusing points. In English, both often look like the “subject,” so it is natural to wonder which one to use.
However, in Japanese, は and が play very different roles. は introduces the topic of the sentence, while が highlights the subject or focus.
But the truth is more complicated. It is not enough to simply say “は = topic” and “が = subject.” The choice depends on context, conversation, and sentence structure. In this article, we will explore the essential differences with examples and practical rules.
By the way, I explain in this article why 「は」 is pronounced wa instead of ha.
は and が in Conversation
Imagine this situation:
A child is looking for their mother and asks:
「お母さんは？」
Okaasan wa?
(Where’s Mom?)
Most Japanese speakers would answer:
「お母さんは台所で晩ごはんを作っているよ。」
Okaasan wa daidokoro de bangohan o tsukutte iru yo.
(Mom is cooking dinner in the kitchen.)
Here, the topic is Mom. The sentence provides information about her.
Now, if the child instead asks:
「晩ごはんは？」
Bangohan wa?
(What about dinner?)
The reply will likely be:
「晩ごはんはお母さんが作っているよ。」
Bangohan wa okaasan ga tsukutte iru yo.
(As for dinner, Mom is the one making it.)
Notice how the topic shifts. When dinner is the topic, the information that follows explains who is making it, so が is used.
This shows that は is not always the grammatical subject. Even an object can take は when it becomes the topic. You can think of は as being “pasted over” other case markers (like が or を) to mark the sentence’s topic.
Information (New vs. Known)
One key difference between は (wa) and が (ga) comes from the type of information.
- は = known information (already shared)
- が = new information (what is being introduced)
Let’s imagine this situation:
Two people are standing in front of a doctor’s office. They both see a person near the reception desk and clearly recognize who they are talking about.
その人は医者です。
Sono hito wa isha desu.
(The person is a doctor.)
→ Here, the person is already known to both speakers. The new piece of information being added is “doctor.”
Now imagine a different situation: someone is inside the hospital and does not know who the doctor is. They are asking which person is the doctor. The answer would be:
その人が医者です。
Sono hito ga isha desu.
(That person is the doctor.)
→ In this case, “doctor” is already understood, and the new information is identifying which person plays that role.
In short: in a は sentence, the new information comes after は; in a が sentence, the new information comes before が.
Fairy Tale Example
In Japanese folktales, the pattern is clear:
昔々、あるところにおじいさんとおばあさんが住んでいました。
Mukashi mukashi, aru tokoro ni ojiisan to obaasan ga sunde imashita.
(Once upon a time, an old man and an old woman lived in a certain place.)
At the beginning, “old man and old woman” are new information, so が is used.
Later:
ある日、おじいさんは山へ芝刈りに行きました。
Aru hi, ojiisan wa yama e shibakari ni ikimashita.
(One day, the old man went to cut firewood in the mountain.)
おばあさんは川へ洗濯に行きました。
(Obaasan wa kawa e sentaku ni ikimashita.)
(The old woman went to wash clothes in the river.)
Here, the characters are already known, so は is used.
Sentence Type (Phenomenon vs. Judgment)
Another rule depends on what kind of sentence it is:
- Phenomenon (what you directly observe) = が
- Judgment or evaluation = は
Examples:
雨が降っている。
Ame ga futte iru.
(It’s raining.) — You see the rain happening.
沖縄の海はきれいだ。
Okinawa no umi wa kirei da.
(The sea in Okinawa is beautiful.) — A judgment or evaluation.
社長はよく飲みに行く。
Shachō wa yoku nomi ni iku.
(The president often goes drinking.) — Describing habits or attributes.
Sentence Structure (Subordinate Clauses and Modifiers)
Grammar structure also affects the choice:
- In subordinate clauses → が
- In noun-modifying clauses → が
Examples:
彼がうちに来たとき、私は出かけていた。
Kare ga uchi ni kita toki, watashi wa dekakete ita.
(When he came to my house, I was out.)
私が作った料理はこれです。
Watashi ga tsukutta ryōri wa kore desu.
(This is the dish I made.)
は normally appears only in the main clause, so が is used inside subordinate or modifying clauses.
Other Uses
Contrast with は
は can highlight contrast:
ひらがなは書けますが、漢字は書けません。
Hiragana wa kakemasu ga, kanji wa kakemasen.
(I can write hiragana, but not kanji.)
Or:
雨は降っています。
Ame wa futte imasu.
(It is raining [but not snowing].)
Exclusive が
が can show exclusivity, meaning “this and no other.”
彼が社長です。
Kare ga shachō desu.
(He is the one who is the president.)
Fixed Expressions with が
Some verbs and adjectives always require が for the object. This is not optional—it’s part of Japanese grammar.
Common examples:
- 日本語がわかります (Nihongo ga wakarimasu.) — I understand Japanese.
- 英語が話せます (Eigo ga hanasemasu.) — I can speak English.
- ピアノが上手です (Piano ga jōzu desu.) — Good at piano.
- 先生の声が聞こえます (Sensei no koe ga kikoemasu.) — I can hear the teacher’s voice.
- 富士山が見えます (Fujisan ga miemasu.) — I can see Mt. Fuji.
Summary for Learners
The difference between は and が cannot be explained by one simple rule. But you can keep these points in mind:
- は = topic, known information, general description or evaluation.
- が = subject/focus, new information, direct observation or specific identification.
- Think of は as the “default” particle, and が as used in special cases.
There are three situations where you must always use が:
- With question words and their answers
(だれが来ますか → 田中さんが来ます / Dare ga kimasu ka → Tanaka-san ga kimasu.)Who will come? → Tanaka will come.
- In noun-modifying clauses
(私が編んだセーター / Watashi ga anda sētā)The sweater that I knitted
- In subordinate clauses
(彼が来たら教えてください / Kare ga kitara oshiete kudasai.)Please let me know if he comes.
At higher levels, you will also see が appear as an answer to an unspoken question, such as:
「私がやりましょうか。」 (Watashi ga yarimashō ka.) — “Shall I do it?”
Final Thoughts
The distinction between は and が depends heavily on context and conversation. For learners, start with the simple rule: は = topic, が = subject/focus. Then, pay attention to how Japanese speakers actually shift topics and highlight new information. The more examples you see in real conversation, the more natural this difference will feel.