-자마자 Grammar in Korean: Meaning and How to Use It

Before you start: you should know -고 나서, the plain "after" pattern, and how to make polite past and future sentences. You should also know how to find a verb stem (the dictionary form without its final 다, such as 도착하 in 도착하다). Estimated time: 15 minutes.

What Does -자마자 Grammar Mean?

-자마자 grammar means "as soon as" or "the moment that". It joins two actions and says that the second one follows the first with almost no gap. In 집에 도착하자마자 샤워했어요, the speaker did not rest or eat first. The shower came straight after arriving. The ending is a connective ending (연결 어미, yeongyeol eomi): a form that links one clause to the next.

Two ideas make this pattern different from other "after" patterns. The first is speed: the sentence says the time between the two actions was very short. The second is that the subjects are free. One person can do both things, as in 도착하자마자 샤워했어요, or two people can be involved: 제가 도착하자마자 비가 왔어요 means "As soon as I arrived, it started raining".

The first verb in each example has no tense, and the second example has two different subjects: the class ends, and he runs out. The next section shows how to build the form on every kind of verb.

How Do You Form -자마자?

You form -자마자 by adding it to the verb stem, with nothing in between and no change to the stem. There is only one version of the ending, so you never choose between -자마자 and -으자마자.

Revised Romanization (RR, the official Latin spelling) follows the sounds of the words but does not show tensing caused by a neighbouring sound. So 먹자마자 is written meokjamaja even though it is said [먹짜마자]. RR does show the letters ㄲ, ㄸ and ㅃ when they are written in Hangul, as in 뜨자마자 (tteujamaja).

Stems Ending in a Vowel

Add -자마자 after the vowel and say it as written: 보자마자, 오자마자, 만나자마자, 일어나자마자. There is no sound change, because the ㅈ comes straight after a vowel.

Stems Ending in a Consonant

Add -자마자 after the final consonant. The spelling stays, but the sound changes. A tense consonant is a sharper, tighter sound, written ㄲ, ㄸ, ㅃ, ㅆ or ㅉ when it has its own letter. The Standard Pronunciation Rules (표준 발음법, Articles 9, 11 and 23, with Article 24 for verb stems ending in ㄵ) say that after the final sounds ㄱ, ㄷ and ㅂ, the next ㅈ becomes tense. So the ㅈ of -자마자 is said as ㅉ:

• 먹자마자 [먹짜마자], with final ㄱ.
• 읽자마자 [익짜마자], where ㄺ is said as ㄱ before ㅈ.
• 듣자마자 [듣짜마자], with final ㄷ.
• 돕자마자 [돕짜마자], with final ㅂ.
• 앉자마자 [안짜마자], where ㄵ is said as ㄴ and the ㅈ turns tense.

Verbs built on 하 have their own sound pattern. In 도착하자마자, the final ㄱ of 착 meets the ㅎ of 하, and the two sounds merge into an aspirated ㅋ: [도차카자마자]. After ㄹ, nothing becomes tense: 놀자마자 is said as written.

Irregular Stems and Nouns

Irregular verbs do not change before -자마자. They change their stem only before endings that start with a vowel. The ending -자마자 starts with the consonant ㅈ, so 듣다 stays 듣자마자 (not 들자마자), 돕다 stays 돕자마자 (not 도우자마자), and 모르다 stays 모르자마자.

You cannot put -자마자 after a noun, an adjective or 이다. A noun needs a verb with it: 도착 (arrival) becomes 도착하자마자. For a noun that names a moment, Korean uses other words, such as 도착 즉시 ("immediately on arrival"). Next, here is one full sentence built step by step.

Worked Example: Building a Sentence with -자마자

You build the sentence in five steps, working from the two quick events you want to join. This example makes "I replied as soon as I read the message".

1. Write both actions with their dictionary verbs. 메시지를 읽다 and 답장하다.
2. Decide which action comes first. Reading comes first, so it goes into the -자마자 clause.
3. Find the stem of the first verb. Remove 다 from 읽다. The stem is 읽.
4. Add -자마자. 읽 + 자마자 = 읽자마자, said [익짜마자].
5. Give the last verb its tense and politeness. 답장하다 becomes the polite past 답장했어요. Put the clause first: 메시지를 읽자마자 답장했어요.

Checkpoint. You have it when you can put the sentence into the future without touching 읽자마자. The answer is 메시지를 읽자마자 답장할 거예요 [메시지를 익짜마자 답짱할꺼예요]. Only the last verb changes.

The sentence built here is a statement. The next section shows which tenses and sentence types can follow -자마자.

Which Tenses and Sentence Types Work with -자마자?

The main verb can have any tense or sentence type, and the verb in front of -자마자 stays bare. The ending carries no tense. The time is read from the final verb.

The main clause often has a helper word that stresses speed, such as 바로 ("right away") or 곧바로 ("straight away"): 집에 오자마자 바로 잠들었어요 means "I fell asleep right after I came home". The helper is optional, because -자마자 already says it.

Next comes the pattern that learners confuse with -자마자 most often.

How Is -자마자 Different from -고 나서?

-자마자 stresses speed, while -고 나서 stresses completion. -고 나서 only says that the first action is over before the second one starts, with any amount of time in between. -자마자 says that the gap is almost zero. The lesson on -고 나서 gives the full rules.

Compare two sentences. 샤워를 하고 나서 잤어요 means "I slept after I took a shower", and there could have been a long pause. 샤워를 하자마자 잤어요 means "I fell asleep the moment the shower was over".

The second neighbour is -(으)ㄴ/는 대로, which also means "as soon as" in one of its senses. The lesson on -(으)ㄴ/는 대로 covers it in full, and the page -자마자 vs -는 대로 compares the two. In short, -(으)ㄴ/는 대로 is mostly used for what you will do or ask someone to do, as in 도착하는 대로 전화할게요 ("I will call as soon as I arrive"). -자마자 also reports events that have already happened, so it is the safe choice for past stories.

A quick test: if you can add "right away" to the English without changing the meaning, -자마자 fits. Next are the useful variations of the pattern.

Variations and Edge Cases of -자마자

-자마자 has three useful variations: the shorter -자, the idiom -기가 무섭게 and the set phrase for "as soon as possible".

• -자 (as soon as). In writing and narration, -자 can replace -자마자: 비가 그치자 밖으로 나갔어요 means "As soon as the rain stopped, I went outside". The shorter form sounds more like a story or a news report, and the main verb is usually in the past.
• -기가 무섭게. This is an idiom for "no sooner than". 먹기가 무섭게 졸려요 means "I get sleepy the moment I eat". It exists in speech, but -자마자 is the form to learn first.
• As soon as possible. This is not -자마자. Say 가능한 한 빨리 or 최대한 빨리: 가능한 한 빨리 오세요 means "Please come as soon as possible".

For more neighbours of this pattern, see Time and Sequence. Next are the errors that appear most often.

What Mistakes Do Learners Make with -자마자?

Learners make five common mistakes with -자마자.

1. Putting a past ending in the first clause. Learners write 도착했자마자 샤워했어요. Actually the first verb stays bare, because the final verb already shows the tense.
2. Using it with an adjective. Learners write 날씨가 좋자마자 산책했어요. Actually -자마자 needs an event, and 좋다 is a state. Use -아/어서 if you mean a reason: 날씨가 좋아서 산책했어요.
3. Using it for a slow sequence. Learners write 대학교를 졸업하자마자 오 년 후에 결혼했어요. Actually the pattern says the gap is tiny, so a five-year gap makes the sentence wrong. Use -고 나서.
4. Saying 먹자마자 as a plain [먹자마자]. Learners follow the spelling. Actually the ㅈ is tense after a consonant stem, so say [먹짜마자].
5. Writing 자 마자 with a space. Learners split the ending. Actually -자마자 is one unit and is written without a space.

Whenever you reach for "as soon as", check that both steps are quick events. Now test yourself.

Practice and Answers

These four exercises check the main skills: joining events, repairing a mistake and choosing the right word. Try each one before you read the answers.

Exercise 1: Join the events. Make one sentence with -자마자: 집에 오다 + 잠들다. ("I come home" then "I fall asleep".) Use the polite past.

Exercise 2: Fix the error. A learner writes 도착했자마자 전화했어요. Correct it.

Exercise 3: Choose the right word. You want to say "After dinner I will call you", with no hurry. Is -자마자 right, or -고 나서?

Exercise 4: Translate. "He laughed as soon as he saw me." (see = 보다, laugh = 웃다)

Answer Key

• Exercise 1: 집에 오자마자 잠들었어요. [지베 오자마자 잠드러써요] The first verb 오 takes -자마자, and 잠들었어요 carries the tense.
• Exercise 2: 도착하자마자 전화했어요. [도차카자마자 전화해써요] The first verb loses its past ending.
• Exercise 3: -고 나서. The sentence is 저녁을 먹고 나서 전화할게요 [저녀글 먹꼬 나서 전화할께요]. You do not mean that the call follows at once.
• Exercise 4: 그는 나를 보자마자 웃었어요. [그는 나를 보자마자 우서써요] The bare stem 보 takes -자마자, and the subjects can differ.

If you missed Exercise 1 or 2, return to the five building steps. If you missed Exercise 3, reread the section on -고 나서. Next, plan where to go from here.

What Should You Learn Next after -자마자 Grammar?

The best next lesson is -(으)ㄴ/는 대로, which has a second meaning ("exactly as") and is also used for "as soon as". Then review -고 나서 to keep "completion" and "speed" apart. The full set of timing patterns is on Time and Sequence. To see where -자마자 sits in a study plan, use the Intermediate Grammar list. The modifier forms used by neighbouring patterns are explained in Noun-Modifying Forms.

What this lesson does not cover. It does not cover the written style -자 in depth, the idiom -기가 무섭게, or the use of -자마자 with passive verbs. The level given here, B1, is an editorial estimate based on common textbook order and TOPIK II, not an official grading.

In short, -자마자 grammar attaches to a bare action verb stem, keeps the first clause free of tense, and says that the second action follows at once.

Frequently Asked Questions

What does -자마자 mean? -자마자 means "as soon as" or "the moment that". It links two actions and says the second one follows the first with almost no gap. 집에 도착하자마자 샤워했어요 means "I showered as soon as I got home". The speed of the change is the whole point of the pattern, so it suits sudden or quick reactions.

How do I attach -자마자 to a verb or adjective? Remove 다 from an action verb and add -자마자 to the stem: 보다 becomes 보자마자, 먹다 becomes 먹자마자. The stem never changes, even for irregular verbs such as 듣다 (듣자마자). Adjectives and 이다 do not take it, because the pattern needs a first event that happens at a moment and is then over.

Can -자마자 be used in the past tense? The main verb can be past, present or future, but the verb before -자마자 stays bare. Say 수업이 끝나자마자 뛰어나갔어요, "He ran out as soon as class ended". Do not write 끝났자마자. The final verb carries the tense for the whole sentence, so one tense covers both steps.

Is -자마자 used in speech or only in writing? -자마자 is used in both. It is neutral in tone and common in daily talk, stories and news. A shorter -자 can also express "as soon as" in writing and narration. In speech, watch the sound: after a consonant stem the ㅈ is tense, so 먹자마자 is said [먹짜마자], not [먹자마자].

What is the most common mistake with -자마자? Learners use it for slow sequences, with adjectives, or for "as soon as possible". It needs two quick action events. "As soon as possible" is not -자마자: say 가능한 한 빨리. A second mistake is a past ending in the first clause, as in 도착했자마자. The tense goes on the final verb only.

What is the difference between -자마자 and -고 나서? -자마자 stresses speed: the second action follows at once. -고 나서 stresses completion: the first action is finished, with any amount of time before the second. 샤워를 하고 나서 잤어요 may leave a gap. 샤워를 하자마자 잤어요 says that sleep followed the shower immediately.

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