In English, "as soon as" covers most situations. Japanese at the N1 level has four specialized patterns for expressing "B happens immediately after A" — each with its own personality.
なり — As Soon As (Unexpectedly)
Structure: Verb dictionary form + なり
"A just happened, and then unexpectedly B followed." Often used to describe someone else's actions, with a sense of surprise.
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彼は部屋に入るなり、倒れてしまった。 → As soon as he entered the room, he collapsed.
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子供は母親の顔を見るなり、泣き出した。 → The moment the child saw his mother's face, he burst into tears.
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彼女はドアを開けるなり、大声で叫んだ。 → The moment she opened the door, she screamed loudly.
Key traits of なり: (1) The subject is usually third person; (2) B feels somewhat unexpected; (3) It has a literary tone.
や否や — In the Instant Between Doing and Not Doing
Structure: Verb dictionary form + や否や
Literally "did or didn't" — emphasizes that there is virtually no time gap between A and B.
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彼はいいチャンスと見るや否や、すぐに行動する。 → The moment he spots a good opportunity, he acts immediately.
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ベルが鳴るや否や、生徒たちは教室を飛び出した。 → The instant the bell rang, the students rushed out of the classroom.
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社長が到着するや否や、会議が始まった。 → The moment the president arrived, the meeting started.
Key traits of や否や: (1) Emphasizes "instant switching"; (2) Very literary, common in news reporting; (3) No restriction on the subject's person.
そばから — Just Finished, and It Happens Again (Repetition)
Structure: Verb dictionary form / た-form + そばから
"Just finished A, and B happens again" — and this situation keeps repeating, with a tone of resignation or frustration.
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お客の名前は覚えたそばから、すぐ忘れてしまう。 → I forget customers' names as soon as I learn them.
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部屋を片付けたそばから、子供が散らかす。 → As soon as I tidy up the room, the kids mess it up again.
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教えるそばから忘れていく生徒に、先生は困っていた。 → The teacher was frustrated with students who forgot things as fast as they were taught.
Key traits of そばから: (1) Must describe something that happens repeatedly; (2) Creates a sense of futility between the actions; (3) A's effort is undone by B.
が早いか — Almost Simultaneously
Structure: Verb dictionary form + が早いか
"A happens extremely fast, and B occurs almost at the same time." Emphasizes the sheer speed — A and B feel like they happen in the same instant.
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窓が開くが早いか、小鳥がすぐに飛び出していった。 → The moment the window opened, the little bird flew right out.
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先生の話が終わるが早いか、学生たちは席を立った。 → The instant the teacher finished speaking, the students stood up.
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ドアが開くが早いか、猫が外に飛び出した。 → The moment the door opened, the cat darted outside.
Key traits of が早いか: (1) Emphasizes speed, near-simultaneity; (2) Literary; (3) Often used for scenes of quick reactions.
Comparison Table
| Pattern | Core Nuance | Repetition? | Register |
|---|---|---|---|
| なり | A just happened, then unexpectedly B | One-time | Literary |
| や否や | Zero time gap between A and B | One-time | Literary (news) |
| そばから | Just did A, then B again (futile) | Repeated | Literary/spoken |
| が早いか | A and B almost simultaneous | One-time | Literary |
Quick memory aid:
- なり = unexpected follow-up
- や否や = instant switch
- そばから = repeated futility
- が早いか = simultaneous action
Summary
- なり: Verb dictionary form + なり — A just happened, then unexpectedly B (often third person)
- や否や: Verb dictionary form + や否や — virtually no time gap between A and B
- そばから: Verb dictionary/た form + そばから — A just finished, B happens again (repeated + futile)
- が早いか: Verb dictionary form + が早いか — A and B happen in nearly the same instant
Self-Test
Q1. 「子供は母親の顔を見る＿＿＿、泣き出した。」 Which one fits?
A. そばから B. なり C. が早いか
Show answer
B. なり. "The moment the child saw his mother, he burst into tears" — describing a third person's unexpected reaction, a classic use of なり.
Q2. 「部屋を片付けた＿＿＿、子供が散らかす。」 Which one, and why?
Show answer
そばから. "As soon as I tidy up, the kids mess it up again" — a repeatedly occurring, futile scenario. Only そばから captures this.
Q3. Both や否や and が早いか express "happening in an instant." What's the difference?
Show answer
や否や emphasizes the critical instant "between doing and not doing," while が早いか emphasizes that two actions happen almost simultaneously, highlighting sheer speed. In practice they're very close, but が早いか puts more focus on how fast the reaction was.