[Korean grammar] -자 Expressing the Ordering of Behavior

가: 어제 아이스쇼 잘 갔다 왔어요? 대단했다면서요?
Did you enjoy the ice show yesterday? Is it true that it was really incredible?
나: 네, 아주 멋있었어요. 공연이 시작되자 조명이 다 꺼지면서 공연장 천장에서 눈이 내리기 시작했어요.
Yes, it was so nice. As soon as the show started, the lights all went out, and it started to snow from the ceiling of the concert hall.
가: 와, 진짜요? 인공 눈이겠죠?
Wow, really? Wasn’t it artificial snow?
나: 네, 맞아요. 그리고 음악이 나오면서 다른 선수들이 등장했어요. 마지막으로 김유나 선수가 무대에 등장하자 사람들이 모두 약속이나 한 듯이 기립 박수를 쳤어요.
Yes, that’s right. And then some other skaters appeared while music played. Finally, just as Kim Yuna appeared on the stage, everyone stood up to give a standing ovation in unison as if they had agreed to do so beforehand.

This expression is used to indicate that the action in the following clause occurs just after the completion of the action in the preceding clause. It is mainly used in written language and only attaches to verbs.

• 창문을 열자 상쾌한 바람이 들어왔다.
As soon as I opened the window, a refreshing breeze entered into the room.

• 버스에서 내리자 비가 오기 시작했다.
It started to rain just when I had gotten off the bus.

This expression is used when the situation in the preceding clause is the cause or motivation for some resulting state of affairs stated in the following clause. It is mainly used in written language and only attaches to verbs.
• 날이 어두워지자 북적거렸던 상가 안이 한산해졌다.
As soon as it became dark, the inside of the bustling shopping area emptied of people.

• 회사에 대한 안 좋은 소문이 나자 그 회사의 주가가 폭락했다.
As soon as a negative rumor emerged about the company, its stock plummeted.

While the expressions -자 and -자마자 are interchangeable to the extent that they both indicate that some action occurs immediately after another action ends, the two expressions have the following differences.