目錄
In Chinese, it is easy to use a single “as soon as… then…” construction whenever two events happen close together. In Japanese, however, the grammar changes along with the scene. 「〜が早いか」 often appears when one event has barely happened before the next reaction bursts out almost immediately. 「〜や否や」 is similarly fast, but its tone is harder and more commonly found in novels, reports, or formal narration. 「〜なり」 often follows the same person continuously, with one action finishing and the next action immediately following. 「〜かと思うと」 is especially suitable when a situation changes so quickly that it feels surprising: someone was just crying and is already laughing, or a train has only just started moving and then stops again. All four patterns can look very similar in translation, but their differences become much clearer when placed back into actual scenes. In particular, whether the subject changes between the two clauses and whether the second clause describes a person’s continuous action or a sudden change usually tells you more about which pattern to use than the translation itself.
What Japanese Patterns Mean “As Soon As…”? Comparing 「〜が早いか／〜や否や／〜なり／〜かと思うと」
「〜が早いか」「〜や否や」「〜なり」「〜かと思うと」 can all describe two events happening in rapid succession, but they do not express the same kind of “speed.” 「〜が早いか」 particularly emphasizes how quickly the second action occurs, 「〜や否や」 records an immediate sequence in a more formal written style, 「〜なり」 often follows the same person into the next action, while 「〜かと思うと」 carries the feeling that the change happens so quickly that it is surprising.
Among them, 「〜が早いか」「〜や否や」「〜なり」 are commonly listed as JLPT N1 grammar, while 「〜かと思うと／〜かと思ったら」 is generally classified as N2. It is reasonable to compare them together in reading practice, but their grammar levels are not exactly the same.
- Example: ベルが鳴るが早いか、生徒たちは教室を飛び出した。
Kana: ベルがなるがはやいか、せいとたちはきょうしつをとびだした。
Translation: As soon as the bell rang, the students immediately rushed out of the classroom.
The students’ action occurs almost right on top of the bell ringing. 「〜が早いか」 strongly highlights how quickly they run out. - Example: 彼は帰宅するなり、ソファーに倒れ込んだ。
Kana: かれはきたくするなり、ソファーにたおれこんだ。
Translation: As soon as he got home, he collapsed onto the sofa.
Both arriving home and collapsing are actions performed by 「彼」, with almost no pause between them. This is a very typical 「〜なり」 scene. - Example: 赤ちゃんは泣いたかと思うと、今度は笑い出した。
Kana: あかちゃんはないたかとおもうと、こんどはわらいだした。
Translation: The baby had just started crying when it suddenly began laughing.
What stands out here is how quickly the situation shifts from crying to laughing, rather than simply how early the second event occurs.
Japanese 「〜が早いか／〜や否や／〜なり／〜かと思うと」 Conjugation Rules and Restrictions on the Second Clause
All four patterns mainly attach to verbs, but their conjugation rules and restrictions on the second clause differ. 「〜や否や」 and 「〜なり」 basically attach to the dictionary form. 「〜かと思うと」 is generally taught with the verb た-form as its basic structure. 「〜が早いか」 most commonly appears with the dictionary form, although some grammar references also list the た-form. For JLPT preparation or when first making your own sentences, using 「V dictionary form＋が早いか」 consistently is less likely to cause confusion.
| Pattern | Basic Structure | Main Image | Subject | Common Style |
|---|---|---|---|---|
| 「〜が早いか」 | V dictionary form＋が早いか | The moment A happens, B almost explodes into action | May differ | Written, narrative |
| 「〜や否や」 | V dictionary form＋や否や | As soon as A happens, B immediately follows | May differ | Formal written style |
| 「〜なり」 | V dictionary form＋なり | After completing one action, immediately moves to the next | Usually the same | Written, narrative |
| 「〜かと思うと」 | Vた-form＋かと思うと | One state has barely appeared before an unexpected change follows | May differ, but usually not used for the speaker’s own intentional action | General narration, conversation |
These patterns also share one major restriction: they are mainly used to describe events that actually occurred. They are not suitable for arranging future plans, nor do they normally take commands, requests, invitations, or other content describing what someone is supposed to do next. For example, “Please contact me as soon as you arrive at the office” should be 「会社に着いたらすぐ連絡してください」, not 「〜や否や」 or 「〜が早いか」.
How to Use 「〜が早いか」｜The First Event Has Barely Happened When the Next Action Bursts Out
「〜が早いか」 compresses two events until it is almost impossible to distinguish which came first. It is especially suitable when the second clause contains a fast reaction such as rushing out, standing up, cheering, or running away. The subjects of the two clauses do not need to be the same, so it can be used for scenes such as a door opening and a cat running outside, or a bell ringing and students rushing out of the classroom.
The 「早い」 in this pattern does not simply mean “early,” nor is it comparing which of two things is faster. The entire expression functions as a fixed temporal pattern, so it is more useful to understand it directly as “the moment… immediately…” or “as soon as…”
- Example: ドアが開くが早いか、猫が外へ飛び出した。
Kana: ドアがあくがはやいか、ねこがそとへとびだした。
Translation: As soon as the door opened, the cat rushed outside.
The subject of the first clause is the door, while the subject of the second is the cat, so different subjects are possible. The focus is that the door has barely opened before the cat is already outside. - Example: 試合開始の笛が鳴るが早いか、観客席から大きな歓声が上がった。
Kana: しあいかいしのふえがなるがはやいか、かんきゃくせきからおおきなかんせいがあがった。
Translation: As soon as the whistle blew to start the match, a huge cheer erupted from the stands.
The whistle acts as the trigger, and the cheering appears almost simultaneously, giving the sentence a strong sense of live speed. - Example: 男は警察官の姿を見るが早いか、反対方向へ走り出した。
Kana: おとこはけいさつかんのすがたをみるがはやいか、はんたいほうこうへはしりだした。
Translation: The moment the man saw the police officer, he started running in the opposite direction.
Seeing the officer and starting to flee are almost one continuous moment, and the second clause 「走り出した」 matches the urgency of 「〜が早いか」 very well.
How to Use 「〜や否や」｜A Formal Written Way to Say “As Soon As…”
「〜や否や」 similarly means that the second event occurs immediately after the first, with an extremely short time gap. Compared with 「〜が早いか」, however, it does not focus as strongly on how explosively fast the second event is. Instead, it feels more like formally recording two events that occur in rapid succession.
The character 「否」 is read 「いな」. This pattern appears more often in news, reports, novels, and formal narration. In everyday conversation, if you simply want to say “I went to sleep as soon as I got home,” forms such as 「〜たらすぐ」 or 「〜たとたん」 sound more natural.
- Example: 知らせを聞くや否や、彼女は駅へ向かった。
Kana: しらせをきくやいなや、かのじょはえきへむかった。
Translation: As soon as she heard the news, she immediately headed to the station.
She leaves immediately after hearing the news. The content itself is straightforward, but 「〜や否や」 gives the sentence a clearly written tone. - Example: 会長は会場に入るや否や、関係者に質問を始めた。
Kana: かいちょうはかいじょうにはいるやいなや、かんけいしゃにしつもんをはじめた。
Translation: As soon as the chairman entered the venue, he began questioning the people involved.
Entering and questioning happen one after another, making this natural in a report or event record. - Example: 玄関のドアが開くや否や、子どもが駆け寄ってきた。
Kana: げんかんのドアがあくやいなや、こどもがかけよってきた。
Translation: As soon as the front door opened, the child came running over.
The subjects are the door and the child respectively, and 「〜や否や」 still works. This is also an easy way to see the difference from the typical use of 「〜なり」.
How to Use 「〜なり」｜The Same Person Finishes One Action and Immediately Moves to the Next
The 「〜なり」 that means “as soon as…” very often follows the same person. Someone comes home and immediately collapses, hangs up the phone and immediately starts complaining, or sits down and instantly begins looking through documents. The two actions form one continuous line with almost no pause.
Grammar explanations usually treat “same subject in both clauses” as an important feature of 「〜なり」. Actual usage is not completely free of examples with different subjects, but for Japanese learning and sentence creation, understanding it first as “continuous actions by the same person” is the safest approach and also the easiest way to distinguish it from 「〜が早いか」 and 「〜や否や」.
- Example: 部長は席に着くなり、資料に目を通し始めた。
Kana: ぶちょうはせきにつくなり、しりょうにめをとおしはじめた。
Translation: As soon as the department manager sat down, he began looking through the documents.
Both sitting down and checking the documents are actions performed by the manager, with almost no pause. - Example: 彼は電話を切るなり、メモを取り出した。
Kana: かれはでんわをきるなり、メモをとりだした。
Translation: As soon as he hung up the phone, he took out a note.
The camera stays with the same person, moving directly from hanging up to taking out the note, which is a typical 「〜なり」 narrative flow. - Example: 子どもは母親の顔を見るなり、泣き出した。
Kana: こどもはははおやのかおをみるなり、なきだした。
Translation: As soon as the child saw their mother’s face, they began to cry.
Both seeing the mother and crying happen to the child. Although the second clause is not a deliberately planned action, it is still an immediate response from the same subject.
How to Use 「〜かと思うと」｜One State Has Barely Appeared Before Another Change Follows
「〜かと思うと」 is easily misunderstood because of the literal 「と思う」 inside it. It can sometimes be translated as “just when I thought…,” but that does not mean every sentence describes someone consciously making a judgment first. This pattern often describes two changes occurring so quickly that the first state barely seems established before the next one appears.
Therefore, its difference from 「〜が早いか」 is not simply one of speed. 「〜かと思うと」 often carries surprise, contrast, or unpredictability, and it is normally not used to describe a sequence of actions that the speaker intentionally decides to perform.
- Example: 赤ちゃんは泣いたかと思うと、すぐに笑い出した。
Kana: あかちゃんはないたかとおもうと、すぐにわらいだした。
Translation: The baby had barely started crying when it immediately began laughing.
The rapid shift between crying and laughing matters more than the simple fact that the second event happens quickly. - Example: 電車が動き出したかと思うと、また止まった。
Kana: でんしゃがうごきだしたかとおもうと、またとまった。
Translation: The train had just started moving when it stopped again.
It looked as though service had resumed, only for that state to be overturned immediately. - Example: 空が急に暗くなったかと思うと、大粒の雨が降り始めた。
Kana: そらがきゅうにくらくなったかとおもうと、おおつぶのあめがふりはじめた。
Translation: The sky had barely turned dark when large raindrops began to fall.
The two events are not necessarily opposites, but the second change arrives quickly and suddenly, which also fits 「〜かと思うと」.
Complete Comparison of Japanese 「〜が早いか」「〜や否や」「〜なり」「〜かと思うと」
What you really need to compare is not the translation, but why the second event follows so quickly. 「〜が早いか」 highlights speed, 「〜や否や」 gives a formal record-like tone, 「〜なり」 follows the same person, while 「〜かと思うと」 describes sudden change and surprise.
| Comparison | 「〜が早いか」 | 「〜や否や」 | 「〜なり」 | 「〜かと思うと」 |
|---|---|---|---|---|
| Basic meaning | As soon as… immediately… | The moment… then… | As soon as one action is completed… | Barely had… when… |
| Basic structure | V dictionary form＋が早いか; some sources also list Vた-form | V dictionary form＋や否や | V dictionary form＋なり | Vた-form＋かと思うと |
| Time gap between clauses | Extremely short, nearly simultaneous | Extremely short, second event immediately follows | Extremely short, next action directly follows the first | Extremely short, a new change occurs just after the first state appears |
| Main focus | How extremely quickly the second event occurs | Objectively and formally recording events in rapid succession | Two actions by the same subject with almost no pause | Conditions change too quickly, often with surprise |
| Subjects | Can differ | Can differ | Usually the same | Can differ |
| Typical second clause | Rushing out, standing up, fleeing, cheering, etc. | Departing, beginning an action, an event occurring, etc. | Same person immediately performs another action or reaction | Change of state, reversal, another sudden event |
| Must the second clause be unexpected? | No | No | No | Often surprising or unexpected, but not necessarily completely opposite |
| Can the second clause be a deliberate human action? | Yes, mainly describing events that already happened | Yes, mainly describing events that already happened | Yes, and very commonly | Can describe a third party, but usually not the speaker’s own deliberate decision |
| Can it arrange future plans? | No | No | No | No |
| Can it take commands / requests? | No | No | No | No |
| Suitable for the speaker’s own intentional actions? | Generally not used for future personal plans | Generally not used for future personal plans | Can describe continuous actions already performed by oneself or others | Usually avoids the speaker’s own intentional actions |
| Core nuance | “So fast you can hardly tell which came first” | “The moment it happened, the next event followed” | “This person did A, then immediately did B” | “It was just like this, and then suddenly it changed” |
| Written-language level | Very high | Very high | Relatively high | Medium |
| Frequency in everyday conversation | Low | Very low | Low | 「〜かと思ったら」 is more common in speech |
| Common text types | Novels, articles, narration | News, reports, formal writing, novels | Novels, character narration | General narration, novels, conversation |
| Best mental image | A acts like a switch and B bursts out immediately | Formally recording B occurring immediately after A | The camera keeps following the same person | The camera watches the same situation suddenly change |
| Typical example | ベルが鳴るが早いか、生徒たちは教室を飛び出した。 | 知らせを聞くや否や、彼女は駅へ向かった。 | 彼は帰宅するなり、ソファーに倒れ込んだ。 | 赤ちゃんは泣いたかと思うと、すぐに笑い出した。 |
| Natural English translation | As soon as the bell rang, the students rushed out of the classroom. | As soon as she heard the news, she headed to the station. | As soon as he got home, he collapsed onto the sofa. | The baby had barely begun crying when it started laughing. |
| Most easily confused with | 「〜や否や」 | 「〜が早いか」「〜なり」 | 「〜や否や」 | 「〜たとたん」「〜かと思ったら」 |
| Difference from 「〜が早いか」 | — | Less emphasis on the explosive speed of the second event; stronger formal written tone | More concerned with whether the same subject performs continuous actions | Focus is not speed itself but rapid change |
| Difference from 「〜や否や」 | Stronger sense of speed in the second event | — | Usually the same subject in both clauses | Carries a sense of change or surprise rather than simple sequence |
| Difference from 「〜なり」 | Does not require the same subject | Does not require the same subject | — | Does not focus on the same person doing A and then B |
| Difference from 「〜かと思うと」 | Describes events happening quickly | Describes rapid succession of events | Describes continuous actions by one person | — |
| Common JLPT classification | JLPT N1 | JLPT N1 | JLPT N1 | JLPT N2 |
▌「〜が早いか」 vs 「〜や否や」｜The Former Emphasizes Speed More, the Latter Sounds More Like a Formal Record
「〜が早いか」 and 「〜や否や」 overlap considerably. The subjects of the two clauses may differ in both patterns, and both frequently appear in written narration. The easiest difference to remember is that 「〜が早いか」 more readily makes the second reaction feel forceful and extremely fast, while 「〜や否や」 has a harder written tone, almost as if formally recording that one event happened and the next immediately followed.
✅ 警報が鳴るが早いか、人々は出口へ走り出した。
As soon as the alarm sounded, people immediately ran toward the exit.
✅ 警報が鳴るや否や、人々は避難を始めた。
As soon as the alarm sounded, people began evacuating.
The first sentence contains 「走り出した」, which already has a strong sense of speed and therefore fits 「〜が早いか」 particularly well. The second sounds very natural in an incident report or formal narrative with 「〜や否や」.
▌「〜なり」 vs 「〜や否や」｜First Check Whether the Subject Is the Same Person
The typical scene for 「〜なり」 is one person doing A and then immediately doing B themselves. 「〜や否や」 does not have this same restriction, so when one external event triggers another person’s reaction, 「〜や否や」 is easier to use.
✅ 彼は玄関を開けるなり、靴を脱いだ。
As soon as he opened the front door, he took off his shoes.
✅ 玄関のドアが開くや否や、子どもが駆け寄ってきた。
As soon as the front door opened, the child came running over.
The first sentence follows 「彼」 through both actions, so 「〜なり」 works. In the second, the first clause describes the door opening and the second switches to the child’s action, making 「〜や否や」 more typical.
▌「〜かと思うと」 vs 「〜たとたん」｜One Focuses on Rapid Change, the Other on the Exact Moment Something Happens
「〜たとたん」 can also be translated as “as soon as…,” but it focuses on the exact moment one action is completed and another event suddenly follows. 「〜かと思うと」 more readily highlights a rapid shift in state, often creating the feeling of “Wasn’t it just like that a moment ago?”
✅ 静かになったかと思うと、また笑い声が聞こえてきた。
It had barely become quiet when laughter could be heard again.
✅ 立ち上がったとたん、めまいがした。
The moment I stood up, I suddenly felt dizzy.
The first sentence focuses on the quick change from quiet to hearing laughter again. The second focuses on dizziness happening at the exact moment of standing up.
▌Does 「〜かと思うと」 Always Mean “I Thought…”? Not Necessarily
Because 「思う」 appears inside the form, it is easy to interpret every sentence as someone literally first making the judgment “I thought A.” In actual use, many sentences simply use this structure to describe how quickly a situation changes.
△ 赤ちゃんが泣いたと思った。
I thought the baby cried.
✅ 赤ちゃんは泣いたかと思うと、すぐに笑い出した。
The baby had barely begun crying when it immediately started laughing.
The second sentence focuses on the rapid switch from crying to laughing. There is no need to force an interpretation in which the speaker literally pauses to think, “The baby is crying.”
▌Can’t These Four Patterns Be Used for “Contact Me as Soon as You Arrive”? Use 「〜たらすぐ」 for Commands and Requests
「〜が早いか」「〜や否や」「〜なり」「〜かと思うと」 all describe events and are not suitable for telling someone what to do next. Although “Contact me as soon as you arrive” looks like the same “as soon as…” pattern in translation, its function is different in Japanese.
❌ 会社に着くや否や、連絡してください。
✅ 会社に着いたらすぐ、連絡してください。
The second clause 「連絡してください」 is a request, not a description of an event that already happened, so 「〜たらすぐ」 is much more natural.
▌Comparing 「〜が早いか」「〜や否や」「〜なり」「〜かと思うと」 in the Same Situation
The differences between the four patterns become clearer when used for the exact same event. Suppose the scene is fixed as “He entered the classroom and immediately opened the window.” Nothing about the actual event changes. Only the grammar in the middle changes, and that shifts what the sentence focuses on. One version highlights the speed of opening the window, another formally records the sequence, while another keeps the viewer’s attention on the same person’s continuous movements.
- Example: 彼は教室に入るが早いか、窓を開けた。
Kana: かれはきょうしつにはいるがはやいか、まどをあけた。
Translation: As soon as he entered the classroom, he immediately opened the window.
「〜が早いか」 makes 「窓を開けた」 feel especially fast, almost as if he had barely stepped into the room before his hand was already reaching for the window. The most noticeable point is how rapidly the second action appears, with the two events almost overlapping. - Example: 彼は教室に入るや否や、窓を開けた。
Kana: かれはきょうしつにはいるやいなや、まどをあけた。
Translation: As soon as he entered the classroom, he immediately opened the window.
「〜や否や」 describes nearly the same sequence, and the timing is still very fast, but the sentence feels more like a formal record of what happened: after entering the classroom, opening the window immediately followed. It does not push the urgency of the window-opening itself as strongly to the foreground, and its written tone is clearer than 「〜が早いか」. - Example: 彼は教室に入るなり、窓を開けた。
Kana: かれはきょうしつにはいるなり、まどをあけた。
Translation: As soon as he entered the classroom, he opened the window.
「〜なり」 keeps the viewer’s attention on 「彼」. He enters the classroom and then personally goes straight to open the window, with almost no pause. Compared with the previous two sentences, this one is more concerned with how two actions by the same person connect than simply how fast the second event happens. - Example: 彼は教室に入ったかと思うと、すぐに窓を開けた。
Kana: かれはきょうしつにはいったかとおもうと、すぐにまどをあけた。
Translation: He had barely entered the classroom when he immediately opened the window.
「〜かと思うと」 adds more of an observer’s sense of watching things change quickly. It is as though you have only just noticed him entering the classroom before another action appears. The sentence does not simply say that the two actions are close together; it more easily gives the feeling of “He had just done this, and then immediately did that.”
| Comparison | 「〜が早いか」 | 「〜や否や」 | 「〜なり」 | 「〜かと思うと」 |
|---|---|---|---|---|
| Same situation | Opens the window immediately after entering the classroom | Opens the window immediately after entering the classroom | Opens the window immediately after entering the classroom | Opens the window immediately after entering the classroom |
| Strongest nuance | The second action happens extremely quickly | Formally describes two events in rapid succession | The same person continuously performs two actions | The first event barely appears before another change follows |
| Main focus | Speed of the second action | Rapid sequence of events | Continuity of one person’s actions | Speed of the transition between events |
| Is the same person important? | Not necessarily | Not necessarily | Very important; usually the same subject | Not necessarily |
| Written tone | Strong | Very strong | Strong | Weaker |
| Easiest way to remember | So fast they almost happen at once | Formal “as soon as…” | One person does A, then immediately B | Barely A, then immediately B |
Even when all four describe “entering the classroom and immediately opening the window,” 「〜が早いか」 makes the window-opening itself feel especially fast, 「〜や否や」 formally records two tightly connected events, 「〜なり」 keeps following the same person from entering to opening the window, while 「〜かと思うと」 gives the perspective of watching one event appear and another immediately follow. The translations can be nearly identical, but what separates the Japanese patterns is where the sentence places the viewer’s attention.
Everyday Conversation vs Written Japanese With 「〜が早いか／〜や否や／〜なり／〜かと思うと」
「〜が早いか」 and 「〜や否や」 have a relatively low presence in everyday conversation and are more likely to appear in novels, news narration, or formal writing. 「〜なり」 also has a narrative quality and is suited to describing a character’s continuous actions. 「〜かと思うと／〜かと思ったら」 is closer to conversation, especially 「〜かと思ったら」, which is easier to hear in everyday speech.
For that reason, these grammar patterns are often more useful for reading than for direct conversation practice. When you encounter them, first decide whether the text is following a character, describing an event bursting into action, or showing a sudden change in state. That is often more effective than first searching for a translation.
▌Situation ①｜Describing a Quick Reaction in News or an Incident Report
A：警報が鳴るや否や、来場者は避難を始めました。
けいほうがなるやいなや、らいじょうしゃはひなんをはじめました。
As soon as the alarm sounded, visitors immediately began evacuating.
B：係員の誘導もすぐに始まったそうです。
かかりいんのゆうどうもすぐにはじまったそうです。
Apparently, the staff also began guiding people immediately.
📌 Grammar Point: 「〜や否や」 presents the alarm and evacuation as two events occurring in rapid succession. Its tone is formal, making it more natural in incident descriptions than in everyday conversation.
▌Situation ②｜Talking About Someone Falling Asleep Immediately After Getting Home
A：田中さん、昨日は帰宅するなり寝てしまったそうです。
たなかさん、きのうはきたくするなりねてしまったそうです。
Apparently, Tanaka fell asleep as soon as he got home yesterday.
B：かなり疲れていたんでしょうね。
かなりつかれていたんでしょうね。
He must have been exhausted.
📌 Grammar Point: Both arriving home and falling asleep have Tanaka as the subject. 「〜なり」 connects the two actions directly and works very naturally in character narration.
▌Situation ③｜Talking About a Child Whose Mood Changes Quickly
A：さっきまで泣いていたかと思ったら、もう笑っていますね。
さっきまでないていたかとおもったら、もうわらっていますね。
They were crying just a moment ago, and now they’re already laughing.
B：子どもは気分が変わるのが早いですね。
こどもはきぶんがかわるのがはやいですね。
Children’s moods really change quickly.
📌 Grammar Point: The shift from crying to laughing happens within a short period. 「〜かと思ったら」 directly brings out that unexpected change and also sounds more natural in conversation than 「〜が早いか」.
Cultural Notes:
- 「〜が早いか」 and 「〜や否や」 are easy to misread in JLPT passages as simply difficult versions of 「すぐ」. What actually matters is the style. Both are highly narrative temporal expressions, and there is usually no reason to force them into everyday plans or conversations with friends.
- 「〜なり」 has grammatical functions other than the “as soon as…” usage discussed here, such as the example-listing construction in 「電話なりメールなり」. When you see 「なり」, do not judge from the word alone. First check whether it follows a verb dictionary form or a noun.
- 「〜かと思うと」 and 「〜かと思ったら」 are often taught together and have broadly similar functions. 「〜かと思ったら」 appears more easily in conversation, while 「〜かと思うと」 has a somewhat more narrative quality. Both commonly describe rapid changes observed from the outside rather than actions the speaker has planned themselves.
How Do Japanese 「〜が早いか／〜や否や／〜なり／〜かと思うと」 Compare With Korean 「-자마자／-더니」?
Japanese 「〜が早いか」「〜や否や」「〜なり」 can all describe the second event occurring immediately after the first, so they partially overlap with Korean 「-자마자」. However, Korean 「-자마자」 is a general-purpose expression that is also very common in everyday conversation, while these three Japanese patterns carry a more obvious written or narrative tone and differ depending on the subjects and the nature of the events.
「〜かと思うと」 often describes another change happening immediately after one state appears and is relatively close to the Korean use of 「-더니」 that connects a previously observed state with a later change. However, 「-더니」 can also express result, cause, or contrast, so not every 「-더니」 sentence can be translated with 「〜かと思うと」.
◆ Similar Grammar ①: Korean 「-자마자」
Korean 「-자마자」 means that as soon as the first action is completed, the second event immediately occurs. The subjects of the two clauses may be the same or different. Depending on the content, it can correspond to Japanese 「〜が早いか」「〜や否や」 or 「〜なり」, but it does not itself carry the strong written tone of those three Japanese patterns.
- Example: 집에 도착하자마자 소파에 누웠어요.
Romanization: ji-be do-chak-ha-ja-ma-ja so-pa-e nu-wo-sseo-yo.
Translation: As soon as I got home, I lay down on the sofa.
Arriving home and lying down are actions performed by the same person, so it can be compared with Japanese 「家に帰るなり、ソファーに横になった」. However, 「-자마자」 is completely natural in everyday Korean, while 「〜なり」 has a clearer written and narrative quality. - Example: 문이 열리자마자 사람들이 밖으로 나갔어요.
Romanization: mu-ni yeol-li-ja-ma-ja sa-ram-deu-ri ba-kkeu-ro na-ga-sseo-yo.
Translation: As soon as the door opened, people went outside.
The subject of the first clause is the door, while the second switches to the people, showing that 「-자마자」 does not require the same subject. This type of objective description of events occurring in sequence can be compared with Japanese 「ドアが開くや否や、人々は外へ出ていった」. - Example: 종이 울리자마자 학생들이 교실 밖으로 뛰어나갔어요.
Romanization: jong-i ul-li-ja-ma-ja hak-saeng-deu-ri gyo-sil ba-kkeu-ro ttwi-eo-na-ga-sseo-yo.
Translation: As soon as the bell rang, the students rushed out of the classroom.
The bell ringing and the students rushing out happen with almost no time gap, so this can be compared with Japanese 「ベルが鳴るが早いか、生徒たちは教室を飛び出した」. 「〜が早いか」 places stronger emphasis than 「-자마자」 on just how rapidly the second event occurs.
◆ Similar Grammar ②: Korean 「-더니」
「-더니」 can connect an action or state previously observed by the speaker with a later change, result, or contrast. When a sentence describes the same subject rapidly changing within a short period, it can be relatively close to Japanese 「〜かと思うと」.
- Example: 아이가 울더니 금방 다시 웃었어요.
Romanization: a-i-ga ul-deo-ni geum-bang da-si u-seo-sseo-yo.
Translation: The child was crying, then quickly started laughing again.
「-더니」 connects the crying previously observed by the speaker with the later laughter and can be compared with Japanese 「子どもは泣いたかと思うと、すぐにまた笑い出した」. The Japanese pattern expresses the rapid switch between crying and laughing more clearly. - Example: 하늘이 갑자기 어두워지더니 굵은 빗방울이 떨어지기 시작했어요.
Romanization: ha-neu-ri gap-ja-gi eo-du-wo-ji-deo-ni gul-geun bit-bang-u-ri tteo-reo-ji-gi si-jak-hae-sseo-yo.
Translation: The sky suddenly turned dark, and then large raindrops began to fall.
「-더니」 connects the sky becoming dark with the beginning of the rain and can be compared with Japanese 「空が急に暗くなったかと思うと、大粒の雨が降り出した」. Korean may also encourage an interpretation in which the dark sky is a sign of the coming rain, while Japanese emphasizes the rapid succession of the two events more strongly. - Example: 고양이가 가만히 앉아 있더니 갑자기 창가로 뛰어갔어요.
Romanization: go-yang-i-ga ga-man-hi an-ja it-deo-ni gap-ja-gi chang-ga-ro ttwi-eo-ga-sseo-yo.
Translation: The cat had been sitting quietly, then suddenly ran toward the window.
「-더니」 contrasts the cat’s earlier still state with its later rapid movement and can be compared with Japanese 「猫はじっと座っていたかと思うと、急に窓辺へ駆け出した」. Both sentences show the same subject undergoing a clear change within a short period.
◆ Differences From the Four Japanese Rapid-Sequence Patterns:
Korean 「-자마자」 is a general “as soon as…” expression, can be used naturally in everyday conversation, and does not require the subjects of the two clauses to be the same. Japanese, however, selects among 「〜が早いか」「〜や否や」「〜なり」 according to narrative focus: 「〜が早いか」 emphasizes that the second event happens almost simultaneously with the first, 「〜や否や」 often objectively describes events occurring one after another, and 「〜なり」 more often follows the same person immediately performing the next action. All three are more literary than 「-자마자」.
When these four Japanese patterns are compared together, there is no real need to memorize them as four different versions of “as soon as…” Reading how the events connect is usually faster. 「〜が早いか」 often makes the second reaction feel especially urgent, 「〜や否や」 works well for formally describing events in rapid succession, 「〜なり」 often follows one person directly from one action into another, while 「〜かと思うと」 frequently appears when one situation has barely emerged before another change immediately follows. For expressions such as “Contact me as soon as you arrive at the office” or ordinary descriptions such as “Rest immediately after you get home,” which involve future arrangements, requests, or everyday narration, there is no need to force these four patterns into the sentence. 「〜たらすぐ」 or other ordinary expressions are often more natural.
FAQ
They can all be translated similarly, but their usage conditions differ. 「〜が早いか」 emphasizes how extremely quickly the second event occurs, 「〜や否や」 is more formal, 「〜なり」 usually describes continuous actions by the same subject, and 「〜かと思うと」 often describes a rapid and surprising change. Choosing only from the translation can easily lead to the wrong pattern.
Both indicate that as soon as the first event occurs, the second immediately follows, and both are relatively literary. 「〜が早いか」 more easily creates an image of the second clause happening forcefully and extremely quickly, while 「〜や否や」 sounds more like formal narration recording events in rapid succession. Many sentences can take either form, with the difference mainly lying in style and narrative effect.
The typical use normally has the same subject, so for JLPT preparation or when making your own sentences, treating it as a same-subject pattern is the safest approach. For example, in 「彼は帰るなり寝た」, both actions are performed by 「彼」. Examples with different subjects can occasionally be found in actual Japanese, but they should not be treated as the basic rule.
Not necessarily. It can often be translated as “just when I thought…,” but many sentences simply describe one state barely appearing before another change occurs. The focus is on a rapid, unexpected transition, and you do not need to assume that the speaker literally made a conscious judgment first every time.
Usually not. These patterns mainly describe events that have already happened, so the second clause does not normally take requests or invitations such as 「〜てください」 or 「〜ましょう」. To say “Please contact me as soon as you arrive at the hotel,” 「ホテルに着いたらすぐ連絡してください」 is more natural.