せい

せい is used to attribute the cause of something negative. The kanji form 所為(せい) exists but is rarely used; hiragana is standard.

Common patterns

• Noun + のせい: because of (noun)
• Verb (plain form) + せいで: because (verb)
• ～のせいにする: to blame on
• ～のせいか: perhaps because of

Similar words

• おかげ: thanks to (positive cause); せい is for negative causes
• ～ため: because of (neutral, can be positive or negative)

Usage

せい attributes blame or negative causation. For positive outcomes, use おかげ instead.