にわたって details
spanning N; across the whole extent of N — a period, distance, or scope covered in full
台風の影響で、三日間にわたって電車が止まったままだったんだよね。
taifuu no eikyou de, mikkakan ni watatte densha ga tomatta mama datta n da yo ne.
Because of the typhoon, the trains stayed stopped for a full three days straight. casual
この調査は全国の主要都市にわたって行われた。
kono chousa wa zenkoku no shuyou toshi ni watatte okonawareta.
This survey was conducted across major cities nationwide. neutral
- formal
- adnominal
Examples
spanning N; across the whole extent of N — a period, distance, or scope covered continuously or repeatedly, not just a single point within it
台風の影響で、三日間にわたって電車が止まったままだったんだよね。
taifuu no eikyou de, mikkakan ni watatte densha ga tomatta mama datta n da yo ne.
Because of the typhoon, the trains stayed stopped for a full three days straight. casual
この調査は全国の主要都市にわたって行われた。
kono chousa wa zenkoku no shuyou toshi ni watatte okonawareta.
This survey was conducted across major cities nationwide. neutral
交渉は五時間にわたり、深夜まで続けられた。
koushou wa gojikan ni watari, shin'ya made tsuzukerareta.
The negotiations continued for a full five hours, lasting until late at night. formal
Formation
{N}にわたってattaches to noun
Variant notes
- にわたり — て-drop — news reports and official documents; 三年にわたり工事が続いた. Never in casual speech.
- にわたる — sits directly before a noun — 十年にわたる研究 "research spanning ten years"; にわたって cannot sit in that slot.
Related patterns
Similar
Both name a stretch of time, but 間に marks a bounded interval WITHIN which a single event lands at some point (休みの間に本を読んだ — the reading happened once, somewhere inside the break), while にわたって marks the span itself as being continuously or repeatedly covered by the action (三日間にわたって会議が行われた — the meeting occupies the whole three days, not a moment inside them) — swap them and "held over three days" collapses into "held sometime during three days."
Lookalikes
にわたって and にあたって differ by a single mora and are easy to misparse at reading speed, but にわたって measures a SPAN — a period, distance, or scope something continues across (三年にわたって "over a span of three years") — while にあたって marks a single OCCASION or juncture something is done at (試合にあたって "on the occasion of the match") — にあたって never measures a literal span, and にわたって never marks a single point-in-time occasion.