JLPT N2 Comparison

〜とたん vs 〜次第 vs 〜や否や totan · shidai · ya ina ya

とたん describes something happening immediately, often unexpectedly; 次第 commonly introduces prompt action once a condition is met; や否や is a literary “as soon as.” The usual forms are Vたとたん, Vます-stem＋次第, and V-dictionary＋や否や. Use 次第 for announcements or plans, and とたん for sudden developments. Their typical uses are more reliable than a rigid past-versus-future rule.

the moment·as soon as·no sooner than

Structure

How do you form とたん, 次第 and や否や?

Verb［た］＋とたん（に）

開けた→開けたとたん. Use the た-form in this pattern; the following event is usually sudden or unexpected.

Verb［ますstem］／Noun＋次第

決まり次第, 到着次第. Common in plans, requests, and announcements about acting as soon as something is ready.

Verb［dictionary］＋や否や

鳴る→鳴るや否や. A literary immediate-sequence expression, commonly used in narrative.

Verb［dict］＋か＋Verb［ない］＋かのうちに

着くか着かないかのうちに. The long way round, and the only one that says the first action had not quite finished.

Meaning

What's the difference between とたん, 次第 and や否や?

とたん commonly introduces a sudden or unexpected development: 立ち上がったとたん、めまいがした. It is usually unsuitable for stating an intentional next step. The た-form before it does not itself force the whole sentence into past time.

次第 commonly announces prompt action after a condition is met: 決まり次第、ご連絡します. It attaches to the ます-stem or an action noun such as 到着.

や否や is a literary expression for immediate succession. ベルが鳴るや否や、教室を飛び出した is a typical narrative use. The dictionary form before it does not by itself specify the sentence’s tense.

か〜ないかのうちに is the pedantic one, and it earns its length. 家に着くか着かないかのうちに means you had barely arrived — the first action was still finishing when the second landed on top of it. Where とたん draws a line between two events, this one refuses to.

Sentences

6 sentences, word by word

とたん — something you did not plan

plain

、。

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立ち上がった

たちあがった

stood up

plain past of 立ち上がる · 立つ stand ＋上がる rise

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とたん

the moment

written 途端, “the very edge” · only the plain past goes in front

〜とたんN2the moment

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めまい

めまい［2］

dizziness

noun · written 目まい, usually left in kana

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が

marks the subject

particle · the doer, or what the sentence is about

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した

happened

plain past of する · めまいがする is the set phrase

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The moment I stood up, my head swam.

とたん — reporting, never planning

plain

、。

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ドア

ドア［1］

door

noun · from English; a 戸 is more often a sliding one

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を

marks the direct object

particle · pronounced お

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開けた

あけた

opened

plain past of 開ける · transitive; 開く is the intransitive twin

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とたん

the moment

conjunction · instantaneous, and nobody intended the second half

〜とたんN2the moment

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猫

ねこ［1］

cat

noun · counted with 匹

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が

marks the surprise

particle · brand-new information takes が, not は

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飛び出した

とびだした

shot out

plain past of 飛び出す · 飛ぶ fly ＋出す send out

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

次第 — the business promise

polite

、。

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日程

にってい［0］

the schedule

noun · 日 day ＋程 extent

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が

marks the subject

particle · 決まる takes が, because nobody is doing it to it

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決まり次第

きまりしだい

as soon as it's decided

masu-stem 決まり＋次第 · everything after it is still in the future

〜次第N2as soon as

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ご連絡します

ごれんらくします

I will contact you

humble ご〜する · the standard close of a business email

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I'll be in touch as soon as the schedule is settled.

次第 — fine before an invitation

polite

、。

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雨

あめ［1］

rain

noun · 雨が降る is how rain falls

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が

marks the subject

particle · the doer, or what the sentence is about

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止み次第

やみしだい

as soon as it stops

masu-stem 止み＋次第 · 次第 is happy in front of an invitation

〜次第N2as soon as

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出発しましょう

しゅっぱつしましょう

let's set off

volitional of 出発する · an invitation, which とたん could never take

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Let's set off as soon as the rain stops.

や否や — the written one

plain

、。

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ベル

ベル［1］

bell

noun · a school or door bell; a temple bell is 鐘

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が

marks the subject

particle · new information, so が rather than は

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鳴る

なる［0］

to ring

godan verb · intransitive; 鳴らす is the one you do on purpose

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や否や

やいなや

no sooner than

dictionary form ＋や否や · literary; both halves really happened

〜や否やN2no sooner than

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教室

きょうしつ［0］

classroom

noun · 教 teach ＋室 room

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を

marks the place left behind

particle · 出る and 飛び出す take を for the place you leave

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飛び出した

とびだした

burst out

plain past of 飛び出す · all speed, no dignity

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The bell had barely rung before they burst out of the classroom.

か〜ないかのうちに — barely finished

plain

、。

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家

いえ［2］

house; home

noun · read うち when you mean your own

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に

at (the arrival point)

particle · 着く always takes に, never を

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着くか着かないかのうちに

つくかつかないかのうちに

had barely got there when

dictionary form ＋か＋ない-form ＋かのうちに · the first action had not quite finished

〜か〜ないかのうちにN2had barely

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雨

あめ［1］

rain

noun · 雨が降る is how rain falls

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が

marks the subject

particle · brand-new information takes が

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降り出した

ふりだした

started to fall

降る＋出す · 〜出す is the moment something starts

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I had barely got home when it started to rain.

Watch out

Where does this go wrong?

A plan after とたん

家に着いたとたん、電話します is unsuitable as an ordinary promise to call. Use 着いたら or 着き次第 for that planned next step.

次第 pointing backwards

For an ordinary report of a completed event, 決まってすぐ or 決まるとすぐに is clearer. Learn 次第 first through its common use in promises, requests, and announcements.

や否や in conversation

Grammatical, and socially odd. It belongs to novels and news copy. Spoken Japanese reaches for とたん or plain 〜てすぐ.

Also asked

Questions people ask about とたん, 次第 and や否や

Which one is safest if I'm not sure?

Choose by purpose: とたん for a sudden development, 次第 for prompt action after a condition is met, and や否や for literary narration. 〜てすぐに is a useful neutral alternative.

Does 次第 have other meanings?

Two more, and they are unrelated grammar. Noun＋次第だ means “it depends on”: 天気次第です. And 〜次第です closing a formal letter means “that is how things stand.” Same word, different job.

Is とたんに different from とたん?

Both とたん and とたんに are standard. に is optional; it is not a reliable divider between spoken and written Japanese.

Is 〜や the same as や否や?

〜や is the shorter literary variant: 席に着くや、話し始めた. Same meaning, even more compressed, and even more clearly written Japanese.

What about か〜ないかのうちに?

It stresses that the first action had not finished. 言い終わるか終わらないかのうちに — before the sentence was even out of your mouth. とたん would let the first event complete first.

Which of these can follow a noun?

Only 次第: 到着次第, 完成次第, 終了次第. The other three need a verb in front of them.

References

Sources and usage notes

Japan Foundation: とたん（に） and や否や — Compares sudden developments with immediate actions and includes nonpast, habitual や否や.

Shogakukan dictionary: 途端 (via Kotobank) — Defines the immediate moment and the optional に.

Shogakukan dictionary: 次第 (via Kotobank) — Gives the immediate-sequence suffix after verb stems and action nouns.

Shogakukan dictionary: やいなや (via Kotobank) — Defines the immediate-sequence use.

Gakushuin University: 時間的近接関係をあらわす接続機能語の分類 — Compares restrictions and tendencies of immediate-sequence expressions; cautions against equating tendencies with absolute tense rules.

Nearby

Points that live next door

〜かねる vs 〜かねないkaneru · kanenai

cannot bring myself to vs might well

ざるを得ない・しかない・ないわけにはいかないno choice but to

forced, left over, or owed

ものの vs にもかかわらず vs ながらもmono no · ni mo kakawarazu

three formal ways to say although

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