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.
どれがいいですか。
Which one would you like?
これらの本の中でどれが一番面白いですか。
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.
どの電車に乗りますか。
Which train will you take?
どの本があなたのですか。
Which book is yours?
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.
この本はとても面白いですが、昨日読み終えました。
This book, which is very interesting, I finished reading yesterday.
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.
私が昨日買った本は面白い。
The book which I bought yesterday is interesting.
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.
どれが正しいか分からない。
I don't know which is correct.
どの道を行けばいいか教えてください。
Please tell me which road to take.
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.
Which would you prefer, coffee or tea?
Which do you like, red or blue?
In some cases, のだ/んだ can add explanatory tone similar to non-restrictive clauses.
彼は遅刻したのだが、理由を言わなかった。
He was late, which he didn't give a reason for.
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?