adverbial N2 uncommon casualpolitewritten
どうして(だ)か — for some reason / somehow
どうして(だ)か ・ どうしてだか
Meaning
- for some reason / somehow / I'm not sure why, but ~ — the cause is unknown to the speaker
Key sentence
どうしてだか、彼女のことが忘れられない。
For some reason, I just can't forget about her.
Formation
| Attaches to | Form | Example |
|---|---|---|
| Fixed adverbial; stands before the clause | どうして(だ)か + clause | どうしてだか + 落ち着かない |
Examples
どうしてだか、今日は朝から胸騒ぎがする。
For some reason, I've had a bad feeling since this morning.
どうしてだか、彼の言葉が頭から離れない。
Somehow, his words just won't leave my head.
When you can't use it
- Distinct from plain どうして ('why?'), which is a genuine question expecting an answer. With the trailing か (どうしてだか / どうしてか) it becomes a statement — 'for some (unknown) reason' — and the speaker is not asking anything.
Easily confused with
See どうして(だ)か in real sentences
Jengo shows どうして(だ)か the way you actually meet it: inside real Japanese sentences, so it sticks instead of staying an abstract rule.
Study it in JengoSources Compiled with reference to A Dictionary of Advanced Japanese Grammar.