What does ～たとたん（に） mean? Japanese grammar N3

Forming it

How to use it

The moment A happens/finishes, B happens immediately — B is unplanned and surprises the speaker.

• 「Vたとたん」 = the moment A happens, B happens. The clause after MUST describe something unexpected that already occurred: 「ドアを開けたとたん、猫が飛び出した」.
• Not used for something you intend to do next on purpose: 「家に着いたとたん、シャワーを浴びよう」 is wrong — use 「～たらすぐ」 there instead.
• Comparing the “the moment…” group: 「とたん」 (unexpected, already happened) — 「か～ないかのうちに」 (almost simultaneous) — 「次第」 (intend to do B right after finishing A, involves will).

Examples

• ドアを開(あ)けたとたん、猫(ねこ)が飛(と)び出(だ)した。

  The moment I opened the door, the cat dashed out.

• 立(た)ち上(あ)がったとたんに、めまいがした。

  The moment I stood up, I felt dizzy.

Keep in mind

• Attaches to the た form.
• The following clause describes an unintended event — not used with will or a command.

Common mistakes

• Wrong家(いえ)に着(つ)いたとたん、シャワーを浴(あ)びよう。

  As soon as I get home, I take a bath right away.

  Correct家(いえ)に着(つ)いたらすぐ、シャワーを浴(あ)びよう。

  The clause after 「とたん」 must be something unexpected that already happened, not an intention.

• Wrongドアを開(あ)けるとたん、猫(ねこ)が逃(に)げた。

  As soon as I opened the door, the cat ran off.

  Correctドアを開(あ)けたとたん、猫(ねこ)が逃(に)げた。

  Must use the た-form; the dictionary form cannot be used.

Exam tips

• 「たとたん」 = the moment A happens, B happens (unexpected, already occurred); connects to the た-form.

Related patterns

• ～か～ないかのうちに
• ～次第
• ～たら