〜にわたって・〜にわたる

over, throughout (a whole span)

Noun (period, area, number) + にわたって / にわたり · にわたる + Noun

にわたって stresses that something covers a whole span, often a long or wide one: 会議は三時間にわたって続いた, "the meeting went on for a full three hours".

It follows nouns of time (三時間, 二年, 長年), area (全国, 広い範囲) or number (数回, 十回). The emphasis is on the scale: all of it, from end to end.

Before a noun, it becomes にわたる: 十年にわたる研究, "ten years of research". In formal writing, にわたり replaces にわたって.

Compare にかけて, which marks a rough range between two points (AからBにかけて). にわたって takes a single span and says "the whole of it".

Examples

会議かいぎは三時間さんじかんにわたって続つづいた。
The meeting went on for a full three hours.
工事こうじは二年にねんにわたって行おこなわれる。
Construction will be carried out over two years.
全国ぜんこくにわたって、雨あめが降ふった。
It rained right across the country.
十年じゅうねんにわたる研究けんきゅうの結果けっかが発表はっぴょうされた。
The results of ten years of research were announced.
彼かれは長年ながねんにわたって、この町まちのために働はたらいてきた。
He has worked for this town for many years.