Aida and Aida ni: During and While in Japanese

Matte iru aida, hon o yonde ita: I read the whole time I was waiting. Add ni, and the meaning shifts to one event somewhere inside that time.

6 min read

Start speaking free
A person reading on a train while the scenery passes
What you need to know

Aida and Aida ni: During and While in Japanese

Aida and aida ni both translate as during or while, but they frame time differently. Aida on its own means for the whole period, so the main clause is something that continues throughout. Aida ni means at some point within the period, so the main clause is a single event or a change. Choosing between them is one of the small decisions that separates textbook Japanese from natural speech. This guide covers how both attach, the te iru aida pattern, how aida ni compares with uchi ni and mae ni, and aida in its other meaning, between.

Aida alone means for the whole period; the main clause continues throughout

Aida ni means at some point within the period; the main clause is one event

Verbs before aida usually take te iru to show an ongoing state

The same kanji in ma ni au and kono aida are separate words to learn

One word, two ways of framing time

Picture a stretch of time on a line. Aida covers the whole line: whatever you describe filled it from start to finish. Aida ni picks a point on the line: something happened in there, once.

English uses during and while for both, which is why learners often drop the ni or add it where it does not belong.

JapaneseRomajiMeaning
夏休みの間、ずっと実家にいました。Natsuyasumi no aida, zutto jikka ni imashita.I stayed at my parents' home for the whole summer break.
夏休みの間に、運転免許を取りました。Natsuyasumi no aida ni, unten menkyo o torimashita.I got my driving licence during the summer break.

How aida attaches

Aida is a noun, so nouns take no before it. Verbs need to describe an ongoing state, which usually means te iru. State verbs such as iru and aru, and negatives, can go straight before it.

JapaneseRomajiMeaning
留守の間にrusu no aida niWhile I was out
日本にいる間にNihon ni iru aida niWhile I am in Japan
知らない間にshiranai aida niBefore I knew it, without noticing
Before aidaForm to useExample sense
NounNoun plus noDuring the summer break
Action verbTe iru formWhile I was waiting
State verbDictionary formWhile I am in Japan
NegativeNai formWhile I was not paying attention

Aida: the whole stretch

When you use aida without ni, the main clause should last as long as the period does. That is why it so often pairs with te iru, te ita or zutto in the main clause.

It also works for instructions that apply throughout a period, such as keeping quiet while a baby sleeps.

JapaneseRomajiMeaning
待っている間、本を読んでいました。Matte iru aida, hon o yonde imashita.I read a book the whole time I was waiting.
電車に乗っている間、ずっと寝ていた。Densha ni notte iru aida, zutto nete ita.I slept for the entire train ride.
子どもが寝ている間、静かにしてください。Kodomo ga nete iru aida, shizuka ni shite kudasai.Please keep quiet while the child is sleeping.

Aida ni: something happens inside the window

Add ni when the main clause is a single event or a completed change. Something happened, once, at some point within the period.

It is also the natural choice for plans that need to happen before a period ends, such as things to do while you are still in Japan.

JapaneseRomajiMeaning
寝ている間に、地震があったそうです。Nete iru aida ni, jishin ga atta sō desu.Apparently there was an earthquake while I was asleep.
留守の間に、荷物が届いていました。Rusu no aida ni, nimotsu ga todoite imashita.A parcel had arrived while I was out.
日本にいる間に、富士山に登りたいです。Nihon ni iru aida ni, Fujisan ni noboritai desu.I want to climb Mount Fuji while I am in Japan.
知らない間に、雨がやんでいた。Shiranai aida ni, ame ga yande ita.The rain had stopped before I noticed.

Aida ni, uchi ni or mae ni?

All three can describe doing something before or during a period, but they stress different things. Choosing well is mostly about whether you want to sound neutral or urgent.

JapaneseRomajiMeaning
休みの間に、部屋を片付けます。Yasumi no aida ni, heya o katazukemasu.I will tidy my room during the holiday.
明るいうちに帰りましょう。Akarui uchi ni kaerimashō.Let us head home while it is still light.
暗くなる前に帰りましょう。Kuraku naru mae ni kaerimashō.Let us head home before it gets dark.
PatternFocusFeeling
aida niA window with a clear start and endNeutral
uchi niBefore the current situation changesUrgency: while you still can
mae niBefore a specific eventNeutral sequence

Uchi ni and mae ni each have their own guides with more examples. The quick test for aida ni is whether the period has a natural end you can point to.

Aida as between, and words to keep apart

Aida is also the everyday word for between, for places, people and times. And the same kanji appears in several set phrases that do not mean during at all.

JapaneseRomajiMeaning
駅と銀行の間にあります。Eki to ginkō no aida ni arimasu.It is between the station and the bank.
この間、駅で田中さんに会いました。Kono aida, eki de Tanaka-san ni aimashita.The other day I ran into Tanaka at the station.
しばらくの間、お待ちください。Shibaraku no aida, o-machi kudasai.Please wait for a while.
間に合いました。Ma ni aimashita.I made it in time. (read ma, not aida)
  • Do not put a one-off event after aida without ni.
  • Do not use a plain action verb before aida; use te iru.
  • Read kono aida as the other day, not during this.
  • Read ma ni au with ma, and treat it as a separate verb.
Key points

A practical way to improve

Describe a trip or a long wait twice: once with aida for what you did the whole time, and once with aida ni for one thing that happened. Tell the story to your AI Sensei in Unihongo's immersive 3D classroom, then check the session report's corrections for any aida that needed ni.

  1. 1

    Choose one clear goal

    Focus each session on a situation or skill you can actually use.

  2. 2

    Practice actively

    Say complete answers aloud instead of only reading or recognizing Japanese.

  3. 3

    Review and repeat

    Keep useful corrections and revisit the same skill until it feels natural.

FAQ

Frequently asked questions

What is the difference between aida and aida ni?

Aida means the main action filled the whole period. Aida ni means the main action happened at some point inside it. Reading the whole time takes aida; a parcel arriving takes aida ni.

Why is it matte iru aida and not matsu aida?

Aida describes a stretch of time, so the verb before it needs to describe an ongoing state, which te iru provides. State verbs such as iru already describe a state and can go directly before aida.

Is aida ni the same as uchi ni?

They overlap. Aida ni points at a window with a clear end. Uchi ni adds urgency: before the situation changes, while you still can.

Does kono aida mean during this?

No. Kono aida is a set phrase meaning the other day, a few days or weeks ago.

Continue learning

All articles

Turn Japanese knowledge into speaking confidence

Practice with Unihongo's AI Sensei in an immersive 3D classroom, with roleplay missions, pronunciation coaching, useful feedback, and learning games that build your vocabulary while you play.

Start speaking free