は vs が: The Difference Explained Simply

は versus が is the question every Japanese learner eventually agonizes over. The good news: there's a reliable core idea, and most confusing cases fall out of it once you have it. (Note: the topic particle は is pronounced "wa," not "ha.")

The core idea: topic vs subject

• は marks the topic: what the sentence is about. Think of it as "as for X…". The topic is usually something already known or established.
• が marks the subject: who or what is doing/being something, often introducing new information or answering "which one?"

Compare:

• 私は学生です。 — As for me, I'm a student. (は: I'm the topic; being a student is the comment.)
• 誰が来ましたか。 — Who came? → 田中さんが来ました。 — Tanaka came. (が: the answer is new information, it identifies which person.)

Notice the pattern: question words as the subject (誰が, 何が) take が, and so do their answers. You can't topicalize unknown information, so 誰は is wrong.

Five patterns that make it click

1. New information takes が; known topics take は. Introduce something with が, then refer back to it with は:

昔々、おじいさんがいました。おじいさんは山へ行きました。 Once upon a time, there was an old man. The old man went to the mountain.

The first mention (new) uses が; once he's established as the topic, he switches to は.

2. Neutral description of an event uses が. Just reporting what's happening, with no particular topic:

雨が降っています。 — It's raining.

3. Existence (あります / います) uses が.

机の上に本があります。 — There's a book on the desk.

4. は is used for contrast.

コーヒーは飲みますが、お茶は飲みません。 — I drink coffee, but I don't drink tea. The は on each item highlights the contrast between them.

5. With 好き, 上手, ほしい, できる, が marks the "object." These describe a state, and the thing liked/wanted/able is marked with が:

猫が好きです。 — I like cats. 日本語ができます。 — I can speak Japanese.

A shortcut that's right most of the time

When you're answering a question, look at where the new information is:

• If the new/emphasized info is the subject → が. ("Tanaka came.")
• If the subject is already known and the new info is elsewhere → は. ("Tanaka went to the mountain.")

That single test resolves a surprising share of real cases.

Don't try to master it in one sitting

は vs が is something you develop a feel for through exposure: no rule chart substitutes for hearing hundreds of correct sentences until the wrong one sounds wrong. That's why input matters so much; see how to start learning Japanese. For the other core particles, read Japanese particles explained.

Any steady source of correct sentences builds that feel: graded readers, podcasts, or the example sentences you meet while studying vocabulary. The tool matters less than hearing correct Japanese daily.