Meaning & Usage
✨ Basic Meaning
Immediately after something happened or was thought to be the case, something else happened, often unexpectedly or involving a rapid change.
🎯 Primary Function
To describe a sudden and often unexpected change or a rapid sequence of events, where the second event follows immediately after the first.
📋 Grammar Structure
Verb (plain form) + かと思ったら\nい-adjective (plain form) + かと思ったら\ な-adjective (plain form・だ) + かと思ったら\nNoun (plain form・だ) + かと思ったら\n\n*Note: The だ after a noun/na-adjective is often omitted, especially in spoken language.*
🎭 Usage Contexts
Formal Situations
Can be used, but typically in descriptive contexts rather than highly formal or polite requests/commands.
Informal Situations
Very common in everyday conversation to describe dynamic situations.
Written Language
Frequently appears in narratives, articles, and descriptive writing.
Spoken Language
Very common and natural in spoken Japanese.
💡 Common Applications
Describing sudden weather changes
Used to illustrate how the weather can change rapidly from one state to another.
Example: 晴れていたかと思ったら、急に雨が降り出した。 (Harete ita ka to omottara, kyuu ni ame ga furidashita.)
Describing rapid actions or states of a person/thing
Used to show how someone or something quickly changed their action or state.
Example: 彼はさっきまで笑っていたかと思ったら、もう泣いている。(Kare wa sakki made waratte ita ka to omottara, mou naite iru.)
Highlighting an unexpected turn of events
Emphasizes the surprising nature of the second event following the first.
Example: 静かになったかと思ったら、また隣の工事が始まった。(Shizuka ni natta ka to omottara, mata tonari no kouji ga hajimatta.)
Frequency
Moderately frequent in both spoken and written Japanese.
Difficulty
JLPT N2
Example Sentences
今朝は寒かったかと思ったら、昼間は汗ばむくらいの陽気だ。
It was cold this morning, but before I knew it, it was warm enough to make me sweat in the afternoon.
赤ちゃんは今寝たかと思ったら、もう泣き出した。
The baby just fell asleep, and now they’ve already started crying.
店に入ったかと思ったら、すぐに「すみません、閉店です」と言われた。
As soon as I entered the store, I was told, “Sorry, we are closed.”
Notes & Nuances
📌 Important Points
Expresses sudden change or rapid sequence
The key nuance is that the second event happens immediately after the first, often in a way that feels sudden or unexpected from the speaker’s perspective.
Example: 晴れていたかと思ったら、急に曇ってきた。(Harete ita ka to omottara, kyuu ni kumotte kita.) – It was sunny, and then it suddenly got cloudy.
Can imply slight surprise
While not always explicitly stated, the pattern often carries a feeling of surprise because the second event rapidly replaced or followed the first.
Example: 彼はさっきまで怒っていたかと思ったら、もう笑っている。(Kare wa sakki made okotte ita ka to omottara, mou waratte iru.) – He was angry just a moment ago, and now he’s already laughing.
⚠️ Common Mistakes
❌ Using it for simple sequences without suddenness
✅ Use simple 「〜たら」 or 「〜と」 for regular sequences. 「かと思ったら」 emphasizes speed and often unexpectedness.
Incorrect: 宿題が終わったかと思ったら、テレビを見た。(Shukudai ga owatta ka to omottara, terebi wo mita.) – This is just “After finishing homework, I watched TV,” lacking the sudden change nuance. Correct: 宿題が終わったかと思ったら、急に友達から電話がかかってきた。(Shukudai ga owatta ka to omottara, kyuu ni tomodachi kara denwa ga kakatte kita.) – Just when I finished my homework, my friend suddenly called.
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🏛️ Cultural Context
Politeness Level: Generally neutral to slightly informal, depending on the context and surrounding language.
Social Situations: Appropriate for describing dynamic events in various social situations, but perhaps avoided in very stiff, formal speeches.
Regional Variations: Widely used across Japan.
🔍 Subtle Differences
〜かと思ったら vs 〜たとたん（に）
「〜たとたん（に）」 emphasizes the moment something happens and the immediate result. 「〜かと思ったら」 emphasizes the perceived rapid change or unexpectedness from the speaker’s perspective.
When to use: Use 「〜たとたん（に）」 when focusing on the exact instant and immediate consequence. Use 「〜かと思ったら」 when highlighting the sudden transition or surprising shift.
〜かと思ったら vs 〜か〜ないかのうちに
「〜か〜ないかのうちに」 highlights that the second event happened almost at the same time or before the first event was even completed.
When to use: Use 「〜か〜ないかのうちに」 when the two events are nearly simultaneous. Use 「〜かと思ったら」 when the second event follows immediately after the first.
〜かと思ったら vs 〜なり
「〜なり」 is used when a person immediately does something else right after doing a specific action (usually by the same person). 「かと思ったら」 can apply to any subject/event and doesn’t require the same subject.
When to use: Use 「〜なり」 for immediate actions by the same person. Use 「かと思ったら」 for any subject/event with a sudden transition.
📝 Conjugation Notes
Connects to the plain form of verbs, i-adjectives, and nouns/na-adjectives (usually with だ, though だ is often dropped).
🔊 Pronunciation Tips
The 「か」 is usually pronounced with a normal pitch. The whole phrase flows together smoothly.
🧠 Memory Tips
Think of 「〜と思った」(thought that X) + 「〜ら」(if/when) leading to something unexpected happening immediately after. “I thought it was X, but then (immediately) Y happened.”
Vocabulary List
晴れる
hareru
to clear up (weather)
急に
kyuu ni
suddenly
降り出す
furidasu
to start raining/snowing
笑う
warau
to laugh
泣く
naku
to cry
静かだ
shizuka da
quiet
隣
next door
Kanji List
思
おも
think
晴
は
clear up
急
きゅう
sudden
雨
あめ
rain
降
ふ
fall (rain, snow)
出
だ
go out, come out
彼
かれ
he
笑
わら
laugh
泣
な
cry
静
しず
quiet
隣
となり
next door
Practice Exercises
Choose the correct form to complete the sentence: 彼は部屋に入った（ ）、すぐに出て行った。
かと思ったら
たびに
によると
にとって
Choose the sentence that uses 「かと思ったら」 correctly.
私は毎日日本語を勉強するかと思ったら、上手になりたいです。
雨がやんだかと思ったら、また降り始めた。
この本は面白いかと思ったら、友達に勧めました。
彼は医者かと思ったら、弁護士でした。
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