～か～ないかのうちに

How to form it

• Verb (dictionary form) + か + Verb (ない-form) + かのうちに

Register: Neutral

Explanation

Says that the next event happened almost before the first one had finished or properly started.

Stresses extreme closeness in time, with the second event starting at the moment the first is only just beginning.

Examples

1. ベッドに入るか入らないかのうちに、眠ってしまった。

   ベッドにはいるかはいらないかのうちに、ねむってしまった。

   I fell asleep almost as soon as I got into bed.

2. 授業が始まるか始まらないかのうちに、彼は居眠りを始めた。

   じゅぎょうがはじまるかはじまらないかのうちに、かれはいねむりをはじめた。

   He started dozing off almost as soon as the lesson began.

3. 電話を切るか切らないかのうちに、また鳴った。

   でんわをきるかきらないかのうちに、またなった。

   The phone rang again almost as soon as I hung up.

Compare with

• ～や否や: や否や is formal and simple; かないかのうちに stresses overlapping timing.
• ～たとたん(に): たとたん is immediate but not overlapping.

Common mistakes

• Using different verbs in the two slots. The same verb is repeated in positive and negative form.