〜せいで: 'Because Of' (Blame / Negative Cause)
What it means
せいで points at the cause of something bad and quietly says "that's the reason this went wrong." It carries a tone of blame or complaint, so you reach for it when the outcome is negative — a delay, a failure, a cancellation, a problem.
雨のせいで試合が中止になった。
あめの せいで しあいが ちゅうしに なった。
Because of the rain, the match was cancelled.
A noun connects with の: 雨のせいで.
ヤッタンのせいで遅れた。
ヤッタンの せいで おくれた。
We were late because of Yattan.
Clear blame — it was Yattan's fault.
食べ過ぎたせいでお腹が痛い。
たべすぎた せいで おなかが いたい。
My stomach hurts because I ate too much.
A plain-form verb connects directly.
How to form it
せい is a noun, so it attaches the way other nouns do. The connector depends on what comes before:
| Preceding word | Pattern | Example |
|---|---|---|
| Verb (plain) | verb + せいで | 寝坊したせいで遅刻した |
| い-adjective | い-adj + せいで | 暑いせいで眠れない |
| な-adjective | な-adj + な + せいで | 下手なせいで負けた |
| Noun | noun + の + せいで | 病気のせいで休んだ |
Note the two glue particles: a noun takes の (病気のせいで), and a な-adjective takes な (不便なせいで). Verbs and い-adjectives connect bare.
More examples
モチが騒いだせいで、先生に怒られた。
モチが さわいだ せいで、せんせいに おこられた。
Because Mochi made a fuss, we got told off by the teacher.
The result — getting scolded — is clearly bad.
弟のせいでゲームのデータが消えた。
おとうとの せいで ゲームの データが きえた。
My save data got deleted because of my little brother.
のせいで with a person = pinning the blame on them.
風邪のせいか、今日は集中できない。
かぜの せいか、きょうは しゅうちゅう できない。
Maybe because of my cold, I can't concentrate today.
せいか softens it to 'maybe because' — the speaker isn't certain.
せいか and せいにする
Two close relatives are worth knowing:
- 〜せいか = "maybe because…" — you suspect the cause but aren't sure. 年のせいか、最近疲れやすい ("Maybe because of my age, I get tired easily lately").
- 〜せいにする = "to blame ~ on…" — to pin the fault somewhere. 失敗を人のせいにするな ("Don't blame your failure on other people").
You'll also hear bare せい as a noun: 全部あなたのせいだ ("It's all your fault").
せいで vs おかげで vs ので/から
This is the heart of the point. All three connect a cause to a result, but the feeling differs:
- せいで — negative result, often blame: 渋滞のせいで遅れた ("I was late because of the traffic" — annoyed).
- おかげで — positive result, gratitude ("thanks to"): 先生のおかげで合格した ("Thanks to my teacher, I passed").
- ので / から — neutral, no built-in good/bad coloring: 雨が降ったので家にいた ("It rained, so I stayed home").
So the same event can take either framing depending on how you feel about the outcome: あなたのせいで…(complaint) vs あなたのおかげで…(thanks). Picking the wrong one sends the wrong emotional signal.
Common mistakes
- Using せいで for a good result. せいで is for bad outcomes. "Thanks to you, I passed" is あなたのおかげで合格した — never あなたのせいで合格した (that sounds like passing was a misfortune).
- Forgetting の after a noun. It's 雨のせいで, not 雨せいで. Nouns need の; な-adjectives need な (下手なせいで).
- Treating せいで as fully neutral. Where no blame is intended, plain 〜ので or 〜から is safer. せいで always adds a critical tone.
- Mixing up せいで and せいか. せいで states the cause as fact; せいか hedges it ("maybe because"). Use せいか when you're only guessing.
Quick recap
- せいで = "because of" for a negative result, often assigning blame.
- Connectors: noun + の, な-adj + な, verbs and い-adjectives connect bare.
- せいか = "maybe because" (uncertain); せいにする = "to blame on."
- Positive opposite = おかげで; neutral cause = ので / から.
Your turn
Choose せいで, おかげで, or ので/から for each result.
Start the 5-question drill →Frequently asked questions
What's the difference between せいで and おかげで?
せいで marks the cause of a bad result and often assigns blame: 雨のせいで中止になった ('cancelled because of the rain'). おかげで marks the cause of a good result and expresses thanks: おかげで合格した ('thanks to that, I passed').
Can I use せいで for something positive?
No. せいで always carries a negative or blaming tone. For a good outcome use おかげで; for a neutral statement of cause use ので or から.
How do I connect a noun to せいで?
Add の: 病気のせいで休んだ ('I was absent because of illness'). A な-adjective takes な instead (下手なせいで), and verbs and い-adjectives connect with no particle.
What does せいか mean?
せいか means 'maybe because' — you suspect a cause but aren't sure: 疲れのせいか、頭が痛い ('maybe because I'm tired, my head hurts'). せいで states the cause as fact; せいか hedges it.