Translation guide
The English word 'which' is used in questions and relative clauses. In Japanese, there is no direct equivalent; the translation depends on the grammatical function. This guide covers how to express 'which' in questions (choosing from options), in relative clauses, and in other uses.
The speaker wants the listener to select one or more items from a known group.
Used when the choice is from three or more items. It stands alone as a pronoun.
Which one would you like?
Which of these books is the most interesting?
Polite form used when choosing between two items. Can also be used for more than two in formal contexts.
Casual version of どちら, used mainly for two choices.
Used when 'which' modifies a noun. どの attaches directly before the noun.
Which train will you take?
Adding extra information about a noun, often set off by commas in English.
Japanese does not have non-restrictive relative clauses like English. Instead, break the sentence or use conjunctive particles like が or けど to add information.
Identifying a specific item or subset from a larger group.
Japanese relative clauses directly modify the noun without a relative pronoun. The clause comes before the noun.
The noun is understood from context, so only the question word is used.
Used when the noun is omitted because it's clear from context.
Embedding a 'which' question within a larger sentence.
The question word is followed by か to form an embedded question.
I don't know which is correct.
どれ is for three or more items. どちら is polite and originally for two items, but can be used for more in formal settings. どっち is casual and strictly for two choices.
English uses 'which' as a relative pronoun, but Japanese simply places the modifying clause before the noun. There is no word for 'which' in this structure.
コーヒーと紅茶、どちらがよろしいですか。
Which would you prefer, coffee or tea?
Which do you like, red or blue?
Which book is yours?
This book, which is very interesting, I finished reading yesterday.
In some cases, のだ/んだ can add explanatory tone similar to non-restrictive clauses.
He was late, which he didn't give a reason for.
The book which I bought yesterday is interesting.
The town which he lives in is quiet.
（ペンを指して）どれがあなたのですか。
(Pointing at pens) Which is yours?
Please tell me which road to take.