First opened Thursday, February 9, 2006
所為
せい
- head-high (atamadaka): falls after mora 1
How to read it: a line over a kana means the voice is high there, and ↓ marks where it drops. A kana with no line is low. With no ↓ the pitch stays high to the end and does not drop even on a following particle (が, は).
cause, reason, fault
Sei, “cause, reason, fault”, is probably a shift from shoi.
Taken apart
No breakdown is shown for this word: Wiktionary's text for it doesn't give a split that spells the word and joins to its reading, and any other split would be a guess.
In a sentence
お前のせいだぞ。
This is your fault.
君の失敗はジムのせいだ。
You have Jim to thank for your failure.
Sentences are from Tatoeba (CC BY 2.0 FR), picked by fixed rules from a dated export and shown unchanged. Nobody has reviewed them one by one.
What Wiktionary says
Quoted line by line from Wiktionary's Etymology section for this reading, taken from one dated dump so it can't change underneath us. Nothing below is paraphrased.
Not settled
Wiktionary itself hedges on part of this word's origin — those lines are marked below.
- “*/sjowi/ → */sjoi/ → /ɕoi/ → /ɕei/ → /sei/ → /seː/”
- Hedged“Probably a shift from shoi above.”
Source: Wiktionary: 所為 (dump of 2026-09-02), available under CC BY-SA 4.0. Reading, meaning and part of speech from JMdict, and kanji readings from KANJIDIC2 (EDRDG).
Other readings of 所為 on the same Wiktionary page
These describe other words written the same way, not せい. They are quoted for context: the parts, layer and processes of this word are not taken from them.
しょい
- “From Middle Chinese 所為 (MC srjoX hjwe|hjweH). The goon, so likely the initial borrowing.”
そい
- “From Middle Chinese 所為 (MC srjoX hjwe|hjweH). The kan'on, so likely a later borrowing. Compare modern Min Nan reading só͘-ûi, Hakka só-vì.”
What the labels mean
- Sound change
- The pronunciation shifted over the centuries.