Particles #7: Use が to Mark Question Word Subjects
Updated: May 21, 2021
Main Points
Often, questions in Japanese follow the pattern seen in これは何ですか.
However, when the question word is in the subject position instead of the predicate position, you need to replace は with が.
When first learning how to turn statements into questions, we're taught to just add the particle か to the end.
For example, 「このゴルフ場は簡単です」("This golf course is easy") becomes 「このゴルフ場は簡単ですか」("Is this golf course easy?").
However, not all questions follow this pattern. In some cases, you'll want to begin a sentence with a question word (e.g., 誰, 何) just like in English.
This tends to happen when you're asking a question about a verb—for instance, when asking who did something. In these cases, the question word will be the subject of the sentence. In such sentences, the subject must be followed by the particle が instead of は.
Examples
何が起きている？
なにがおきている？
What's happening?
いつが行く？
いつがいく？
When are we going?
誰がすべてのクッキを食べたの？
だれがすべてのクッキをたべたの？
Who ate all the cookies?
どのゴルフ場が簡単ですか。
どのゴルフばがかんたんですか。
Which golf course is easy?
For some questions, you can use either construction: (1) A は [question word] ですか or (2) [question word] が A ですか. The meaning is the same for both patterns.
Examples
先生は誰ですか。
せんせいがだれですか。
Who's the teacher?
誰が先生ですか。
だれがせんせいですか。
Who's the teacher?
Note that when answering a question posed in the second way, your answer should include が as well (e.g., 山川さんが先生です).