N3 Time, Sequences, and Change

~うちに① (Change): meaning, usage and examples

~うちに① (Change) means: while... (something changed).

Updated 9 November 2026 · By the My Senpai team · Spotted a mistake? Tell us

Examples

1. 電話でんわで話はなしているうちに、朝あさになった。

   The day broke while I was talking on the phone.

2. 映画えいがを見みているうちに、寝ねてしまった。

   I fell asleep while watching the movie.

3. 練習れんしゅうしているうちに、上手じょうずになりました。

   As I kept practicing, I got better at it.

4. 歩あるいているうちに、空そらが暗くらくなってきました。

   While we were walking, the sky started getting dark.

When to use it

This うちに means "while doing X for a while, something changed without my noticing." The first part is a continuing action, usually with ている, and the second part is a change that happened gradually or by itself: 話はなしているうちに仲良なかよくなった, "As we talked, we became friends." It often comes with なる, てくる or てしまう.

Nuance

The change is not planned: it happens on its own as time passes, and the speaker often notices it only afterward, like "before I knew it." The second clause is usually in the past tense and is not a command or a wish.

Compare

うちに② (opportunity) means "do it before a state ends": 熱あついうちに食たべて (eat it while it is hot). うちに① reports a change that happened along the way: 歩あるいているうちに雨あめがやんだ. 間あいだに simply places an event inside a period, without the idea of gradual change: 寝ねている間あいだに荷物にもつが届とどいた.

Tip: If English "before I knew it" fits, this is the change meaning. Look for ている before うちに and なった, てきた or てしまった after it.