とたんに

The Moment That

Level 2Sounds Like totanni

The moment Action A finishes, Action B happens suddenly and often surprisingly. It is used with the past tense (た-form) of verbs.

How It Works

The expression とたんに (often written in kanji as 途端に) is used to link two events that happen in very rapid succession.

Key characteristics include:

  • Suddenness: The second event happens almost instantly after the first.
  • Surprise: The speaker often feels surprised or caught off guard by the second event.
  • Lack of Volition: The second clause cannot be an intentional action, command, or request by the speaker. It must be a natural occurrence, an automatic reaction, or someone else's action.
  • Past Tense Focus: This pattern is primarily used to describe things that have already happened.
  • Grammar: It must follow a verb in the た form. The particle に is optional but adds a slight adverbial emphasis.

Examples (4)

  1. 家を出たとたん、雨が降り出した。

    The moment I left the house, it started to rain.

    Word by Word: House (object) exited moment, rain (subject) started falling.

    This shows a sudden, unexpected natural event (rain) occurring immediately after the action of leaving the house.

  2. 犯人は警官の姿を見たとたんに、逃げ出した。

    The moment the criminal saw the policeman, he fled.

    Word by Word: Criminal (topic) policeman's appearance (object) saw moment, fled.

    Here, the second action is a sudden reaction by another person, which is a common use for this pattern.

  3. 立ち上がったとたん、めまいがした。

    The moment I stood up, I felt dizzy.

    Word by Word: Stood up moment, dizziness (subject) did.

    This demonstrates an unintentional physical reaction that happens instantly after a movement.

  4. 窓を開けたとたん、冷たい風が入ってきた。

    The moment I opened the window, a cold breeze came in.

    Word by Word: Window (object) opened moment, cold wind (subject) entered.

    The opening of the window immediately triggered the entry of the wind.

Common Mistakes

  • Using it for the speaker's intentional actions.

    窓を開けたとたんに、外を見た。
    窓を開けたとたんに、冷たい風が入ってきた。

    とたんに is used for sudden, unexpected changes or reactions that happen automatically. It cannot be used for the speaker's own intentional or volitional actions, even in the past. Use 〜たら すぐに for intentional sequences.

  • Using it for future plans or commands.

    ベルが鳴ったとたん、立ち上がりなさい。
    ベルが鳴ったら、すぐに立ち上がりなさい。

    This pattern is almost exclusively used to describe past events that have already occurred. It cannot be used for future plans, commands, or requests. For these situations, use 〜たら or 〜次第.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

とたんにLevel 2The Moment That

Learn This First

To understand とたんに, you need to know how to conjugate verbs into the plain past (た form), as this pattern specifically attaches to that form to mean 'the moment that [action] happened.' Familiarity with the particle に as a time marker and general verb usage is also necessary.

Words in This Pattern

とたんに途端