は vs が: what's the difference?
は marks what the sentence is about; が points out the subject and puts the focus on it. How to choose, with examples and a quick drill.
Draft: written with AI help and not yet checked by a teacher. If something looks wrong, please report it.
The patterns
- はTopic marker — "as for…"No lesson yet
- がSubject marker — points out who or whatNo lesson yet
The difference
は marks the topic — what the sentence is about, usually something already known — and the weight of the sentence falls on what comes after it. が marks the subject and puts the weight on the subject itself: it answers "who?" or "which one?", introduces something new, and is the particle a question word takes when it is the subject (誰が来ましたか, 何が好きですか). A question word can never be the topic, so it never takes は; in other roles it takes its usual particle (何を食べますか, 誰に会いましたか). The topic of a question can still take は: それは何ですか. Inside a clause that describes a noun ("the cake my mother made"), the subject takes が, not は. A few predicates — 好き, 分かる, ある/いる, ほしい — mark the thing liked, understood, owned or wanted with が. は can also contrast: "X, at least (unlike the others)".
Side by side
When a question word is the subject, it takes が, never は. A person you are already talking about is the topic, so は.
は: "about me — I'm a student". が answers "which of you is Tanaka?", so the focus is on 私.
Something new enters the conversation with が; once it is known, it becomes the topic with は.
は can set two things against each other. Inside a clause that describes a noun (母が作った…), the subject takes が.
Quick drill
Pick the word that fits the blank. You get the answer straight away.
誰＿＿この絵を描きましたか。
私＿＿山田です。どうぞよろしく。
机の上に本＿＿あります。
私はりんご＿＿好きです。
これは兄＿＿撮った写真です。
コーヒーは飲みますが、紅茶＿＿飲みません。
どれが田中さんの傘ですか。— この青い傘＿＿田中さんのです。