How to tell them apart
Both point to a cause for a bad outcome, but ばかりに stresses that one single, often minor or unfair factor is the whole reason things went wrong, carrying a sense of "if only that hadn't happened." せいで simply blames a cause for an undesirable result and is commonly used to pin fault on someone or something, as in 誰のせいでもない. Swapping them feels off because ばかりに sounds too dramatic for a neutral blame statement, while せいで lacks the "just because of that one thing" nuance.
- ばかりに Use ばかりに when one small or specific factor alone triggers an unfortunate result.
- せい Use せいで when you want to blame a cause or someone's fault for a bad outcome.
| Grammar point | Meaning | JLPT level |
|---|---|---|
| ばかりに bakarini | merely for the reason that | N2 |
| せい sei | owing to, for the fault of (unfavorable cause) | N3 |
ばかりに bakarini
merely for the reason that
ばかりに attaches to a noun and means something happens simply because of that thing, often with a negative or regretful result. It also appears in the pattern 言わんばかりに, where it follows the volitional form and means someone acts as if to say something.
-
この事ばかりに時間をかけてるわけにはいかないんだ。
You can't just spend all of your time doing this.
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彼女は万事承知と言わんばかりに私に目くばせした。
She winked at me as much as to say she knew everything.
せい sei
owing to, for the fault of (unfavorable cause)
せい attributes a bad result to a cause, often with a nuance of blame. It follows a noun with の, as in 貧しさのせいで, and appears in patterns like せいにする, to blame something on someone. It is used for negative outcomes, not neutral or good ones.
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彼女の失敗の原因を勤勉さがなかったせいにすべきでない。
Her failure is not to be ascribed to want of diligence.
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彼の失敗の原因を勤勉さがなかったせいにすべきではない。
His failure is not to be ascribed to want of diligence.
ばかりに and せい are JLPT N3–N2 grammar points that Japanese learners often mix up. This page compares them side by side on meanings, usage and example sentences, so you can tell them apart.