た途端に details
write + (past) + the moment
kaita totan ni
the moment; no sooner had — an abrupt, usually surprising, consequence
meaning: the moment you write
この財布、開けたとたんに小銭が全部落ちるんだよね。
kono saifu, aketa totan ni kozeni ga zenbu ochiru n da yo ne.
This wallet — the moment you open it, all the change falls out, you know. casual
電気を消したとたんに、電話が鳴った。
denki o keshita totan ni, denwa ga natta.
The moment I turned off the light, the phone rang. neutral
- contraction
Examples
the moment; no sooner had — the second event follows the first so closely it reads as one beat, usually catching the speaker off guard
この財布、開けたとたんに小銭が全部落ちるんだよね。
kono saifu, aketatotanni kozeni ga zenbu ochiru n da yo ne.
This wallet — the moment you open it, all the change falls out, you know. casual
電気を消したとたんに、電話が鳴った。
denki o keshita totan ni, denwa ga natta.
The moment I turned off the light, the phone rang. neutral
開演の合図が鳴ったとたん、会場は静まり返りました。
kaien no aizu ga natta totan, kaijou wa shizumarikaerimashita.
The moment the curtain-up signal sounded, the venue fell completely silent. formal
Formation
{V-ta}とたんにattaches to た-form
Variant notes
- たとたん — に drops freely in speech and casual writing with no register shift — ドアが開[あ]いたとたん、猫[ねこ]が逃[に]げた.
Notes
deliberate, planned main clause (起きたとたんに歯を磨いた) sounds odd.
Related patterns
Similar
とき merely co-locates two events with no claim about how close together they are; とたんに demands the second event follow almost instantaneously and reads as abrupt or surprising by default — 座[すわ]ったとき is a neutral setting, 座ったとたんに椅子[いす]が壊[こわ]れた is a jolt.