Ask who someone is (だれ / どなた)

The Mystery Agent Mental Model

When asking about a person's identity, Japanese uses だれ (who) in casual and polite speech, and どなた in respectful formal contexts.

#### The Golden Rule: だれが vs Never *だれは

One of the most foundational rules in Japanese grammar is: A question word can NEVER be marked by the topic particle は!

Why? • The topic particle は marks already established, shared knowledge (“Speaking of X, which we both know about...”). • An unknown question word (だれ, 何, どこ) cannot be an established topic! • Therefore, when だれ is the subject performing an action, it strictly takes が: - だれが来ましたか: “Who came?” - だれがケーキを食べましたか: “Who ate the cake?” - Answering mirrors the particle: 田中さんが来ました (“Tanaka-san came”).

Combining だれ with Other Particles

When not the subject, だれ takes the standard case particles: • Possession (の): これはだれの傘ですか: “Whose umbrella is this?” • Accompaniment (と): だれと映画を見ましたか: “Who did you watch the movie with?” • Recipient / Target (に): だれに手紙を書きましたか: “Who did you write a letter to?”

The Politeness Ladder: だれ vs どなた vs どちら様

Match the word to social distance: 1. Casual / Standard (だれ): - あの人はだれですか: “Who is that person?” 2. Polite Respect (どなた): - あの方はどなたですか: “Who is that distinguished person?” 3. Formal Reception & Phone (どちら様(どちらさま)): - どちら様でしょうか: “May I ask who is calling / speaking?”