To fold a content question — one with a question word like what, where, when, who, why — inside a larger sentence, Japanese does something wonderfully simple: it takes the question, leaves every word exactly where it stood, caps it with か, and drops the whole thing into a slot. 何を買うか is just the standalone question 何を買うか ("what to buy") set down whole inside a bigger sentence. There is nothing to rearrange — which is precisely the problem for English speakers, because English does rearrange, violently, and the habit is automatic. The one skill this page trains is not doing what English trained you to do.
The frame: question word stays, か closes the clause
Take any content question in plain form, keep its か, and hang a main verb (決める, 分かる, 知る, 教える, 説明する) off the end:
何を買うか決めた。
nani o kau ka kimeta
I've decided what to buy.
どこに行くか分からない。
doko ni iku ka wakaranai
I don't know where to go.
誰が来るか教えて。
dare ga kuru ka oshiete
Tell me who's coming.
Each embedded clause — 何を買うか, どこに行くか, 誰が来るか — is a complete little question, and it fills the object slot of the main verb just as a noun would. Unlike the yes/no frame 〜かどうか, there is no どうか here: the question word itself supplies the openness, so か alone closes the clause.
いつ始まるか知っていますか。
itsu hajimaru ka shitte imasu ka
Do you know when it starts?
どうすればいいか分からない。
dō sureba ii ka wakaranai
I don't know what to do (how I should do it).
なぜ遅れたか説明した。
naze okureta ka setsumei shita
He explained why he was late.
The load-bearing point: Japanese does not front the wh-word
This is the reflex you must consciously suppress, so slow down and look at the two languages side by side. In English, a question word is obligatorily moved to the front of its clause — even when the question is embedded. Watch what leave its natural object position and leap to the front, leaving a gap behind:
- I don't know what he bought _. ← what moved from the object slot to the clause front
The gap (_) marks where what logically belongs — right after bought, as its object — but English refuses to leave it there. This movement is called wh-fronting, and it is so ingrained that English speakers do it without noticing.
Japanese does not move anything. The question word sits in the exact position its answer would occupy, and か is simply added at the end of the clause:
- 彼が 何を 買った か 分からない。 ← 何を stays in the object slot; nothing moves
Line them up:
| Clause structure | |
|---|---|
| English | … what[moved] he bought _ |
| Japanese | 彼が 何を[in place] 買った か |
In 何を買ったか, 何を sits precisely where 本を ("a book") would sit if you were answering — 本を買った. To make the question, you swap 本 for 何 and add か. Nothing travels. The order of a Japanese embedded question is identical to the order of the same standalone question — 何を買うか as a question, 何を買うか as an embedded clause, character for character.
彼が何を注文したか覚えていない。
kare ga nani o chūmon shita ka oboete inai
I don't remember what he ordered.
この漢字をどう読むか教えてください。
kono kanji o dō yomu ka oshiete kudasai
Please tell me how to read this kanji.
In both, the question word (何を, どう) sits mid-clause, right where its answer would go, and the whole clause lands before the main verb — because Japanese is verb-final. The English instinct pushes the question word forward and the clause backward; resist both.
More question words, same recipe
Every content question word works the same way — 何 (what), どこ (where), いつ (when), 誰 (who), なぜ／どうして (why), どう (how), どれ／どちら (which), いくら (how much). Form the question, keep か, embed it:
会議がいつ終わるか分かりません。
kaigi ga itsu owaru ka wakarimasen
I don't know when the meeting ends.
どれがいちばん安いか比べてみた。
dore ga ichiban yasui ka kurabete mita
I compared which one was the cheapest.
When the question word itself is the whole predicate (a noun-type question like 犯人は誰？), だ drops before か, mirroring the direct question:
犯人が誰かまだ分からない。
hannin ga dare ka mada wakaranai
We still don't know who the culprit is.
The のか variant: adding a shade of "the matter of"
Very often, especially with なぜ／どうして, the embedded question appears as 〜のか rather than bare か. The の nominalizes the clause and adds a faint "the question/matter of…" nuance — a sense that there is a real puzzle to be resolved. It is extremely common and slightly softer:
どうして彼が怒っているのか分からない。
dōshite kare ga okotte iru no ka wakaranai
I don't understand why he's angry.
何が起きたのか、誰も知らない。
nani ga okita no ka, dare mo shiranai
Nobody knows what happened.
The word order is unchanged — の simply slips in before か. You can use plain か or のか in most contexts; のか leans reflective, か is more neutral.
Common mistakes
Mistake 1 — Fronting the question word / stranding the clause after the verb. The double English reflex: push the wh-word forward and let the clause trail the main verb.
❌ 私は知らない、彼がどこに行ったか。
English order — the embedded question is stranded after the verb. In Japanese the whole clause comes BEFORE 知らない.
✅ 私は彼がどこに行ったか知らない。
watashi wa kare ga doko ni itta ka shiranai
I don't know where he went.
Mistake 2 — Omitting the clause-final か. Without か there is no embedded question; the two clauses just collide.
❌ 何を買う決めた。
Wrong — the embedding か is missing. It must be 何を買う か 決めた.
✅ 何を買うか決めた。
nani o kau ka kimeta
I've decided what to buy.
Mistake 3 — Adding どうか to a wh-question. どうか is for yes/no only; a question word already carries the openness.
❌ どこに行くかどうか分からない。
Wrong — どうか is yes/no only. With どこ, use plain か: どこに行くか分からない.
✅ どこに行くか分からない。
doko ni iku ka wakaranai
I don't know where to go.
Mistake 4 — Leaving a polite です／ます form inside the embedded clause. The embedded question normalizes to plain form; politeness lives on the outer verb.
❌ いつ始まりますか知っていますか。
Wrong — the embedded clause must be plain: いつ始まるか. The ます/です stays only on the outer verb.
✅ いつ始まるか知っていますか。
itsu hajimaru ka shitte imasu ka
Do you know when it starts?
Key takeaways
- Embed a content question with question word + plain clause + か, then hang the main verb (決める, 分かる, 教える…) off the end.
- No どうか — the question word supplies the openness, so か alone closes the clause.
- The reflex to suppress: no wh-fronting. The question word stays in the exact slot its answer would fill; the embedded question keeps the same order as the standalone question (何を買うか = 何を買うか).
- Because Japanese is verb-final, the whole embedded clause sits before the main verb, never trailing after it as in English.
- 〜のか is a common, slightly reflective variant (どうして…のか分からない); noun-type questions drop だ before か (誰かまだ分からない).
- For yes/no embedding, switch to 〜かどうか.
Now practice Japanese
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Start learning Japanese→Related Topics
- Embedded Yes/No Questions: 〜かどうかN3 — To fold a yes/no question inside a bigger sentence — 'I don't know whether he'll come' — Japanese uses plain form + かどうか, dropping だ before か exactly as a direct question does.
- Quotation with とN4 — と marks the boundary of a thought or utterance treated as content, closing a quoted clause before verbs of saying, thinking, and calling — and by extension introducing intentions, names, and even sounds.
- Embedded and Subordinate ClausesN4 — How Japanese builds a clause into a larger one — as a complement, an adverbial, or a noun-modifier — always right-headed, with the subordinator at the clause's end and the plain form inside.