“〜hazumi de・no ikioi de”: On the Spur of / Carried by the Momentum [JLPT N1]
By Nihongo to Japan · Updated July 3, 2026
Doing something carried along by a moment or momentum
“〜hazumi de・no ikioi de”: On the Spur of / Carried by the Momentum
This pair expresses “doing something on the impulse/momentum of a moment (not after deliberation)”: (noun の／verb た-form) ＋ はずみで = “on the spur of, the impulse of that moment”: 「話のはずみで、つい余計なことを言ってしまった」 (in the flow of conversation, I blurted out something needless), 「転んだはずみで足をひねった」 (twisted my ankle in the moment of falling); noun の ＋ 勢いで = “carried by the momentum of 〜”: 「酒の勢いで告白した」 (confessed on the strength of the drink).
🧠 Core nuance: not planned — carried along by the momentum of the moment
The core is “carried along (involuntarily) by the impulse, inertia, or momentum of the moment”: not after careful thought, but swept along by the inertia of an action or the momentum of emotion (the flow of talk, the physical inertia of falling, the momentum of alcohol). はずみ is “impulse, bounce, the moment”; の勢いで is “carried by the momentum of….” Both stress being non-deliberate, going with the flow, with often unexpected results.
📌 How to Connect
| Form | Pattern | Example |
|---|---|---|
| noun の ＋ はずみで | on the spur of the moment | 話のはずみで |
| verb た-form ＋ はずみで | in the moment of 〜 | 転んだはずみで |
| noun の ＋ 勢いで | carried by the momentum of 〜 | 酒の勢いで |
💬 Example Sentences
- 話のはずみで、つい言わなくてもいいことを口にした。(In the flow of talk, I let slip something I needn't have.) — going with the flow
- 転んだはずみで、足首をひねってしまった。(In the moment of falling, I twisted my ankle.) — physical inertia
- その場のはずみで、引き受けると約束してしまった。(On the spur of the moment, I promised to take it on.) — momentary impulse
- 酒の勢いで、上司に本音をぶつけた。(On the strength of the drink, I let my boss have my true feelings.) — on momentum
- 若さの勢いで、会社を辞めて起業した。(Carried by the momentum of youth, I quit and started a business.) — driven by momentum
🔄 Compare: はずみで vs 勢いで vs ついでに vs うっかり
| Expression | Nuance | Example |
|---|---|---|
| 〜はずみで | “on the spur of / the impulse of the moment” (not deliberate) | 話のはずみで |
| 〜の勢いで | “carried by the momentum of 〜” (emotion/drink/youth) | 酒の勢いで |
| 〜ついでに | “while at it” (doing B while doing A) | 買い物のついでに |
| うっかり | “carelessly” (an oversight) | うっかり忘れた |
⚠️ Common Mistakes
- Dict. form: ✗ 約束するはずみで → noun の/verb た-form ＋ はずみで (転んだはずみで).
- Confusing with ついでに: はずみで = going with the flow/impulse; ついでに = while at it (a purposeful add-on).
- Adding を/だ: ✗ はずみでを言う → はずみで is followed by a verb clause.
- Often an unexpected result: the latter is often an unexpected, unintended outcome.
💡 Nuance & When to Use
はずみで・の勢いで express “doing something on the impulse, inertia, or momentum of the moment (not after deliberation)”: blurting out too much in the flow of talk, twisting an ankle in the inertia of a fall, confessing on the strength of drink, starting a business on the momentum of youth. They stress being non-deliberate, going with the flow, with often unexpected results (said too much, agreed, got hurt). はずみで leans “the impulse/inertia of the moment,” の勢いで “carried by some momentum.” Master “non-deliberate + going with the flow.” A must at N1.
🎯 JLPT Exam Tips
- Commonly tested at N1: noun の/verb た-form ＋ はずみで = on the spur of; noun の ＋ 勢いで = carried by momentum.
- Connection: はずみで takes noun の or the verb た-form.
- Distinction: はずみで (impulse/flow) vs ついでに (while at it) vs うっかり (careless).
🖊️ 練習題（5題）
Q1. 「___、つい余計なことを言ってしまった。」（一時順著話頭）
(A) 話のはずみで (B) 話のおかげで (C) 話のせいで(語感異) (D) 話のために
Q2. 「酒の勢いで」の意味は?
(A) 藉著酒勁
(B) 戒酒之後
(C) 沒喝酒
(D) 討厭酒
Q3. 「転んだはずみで足をひねった」の意味は?
(A) 跌倒的當下扭傷了腳
(B) 故意扭傷
(C) 沒跌倒
(D) 跌倒前扭傷
Q4. 「はずみで」の語感は?
(A) 在那當下的勁頭/慣性下（非深思）
(B) 深思熟慮後
(C) 命令
(D) 條件
Q5. 接法が正しいのは?
(A) その場のはずみで約束した。 (B) 約束するはずみで。
(C) はずみでを言う。 (D) はずみだで言う。
答案解析
1. (A) 話のはずみで ── 一時順著話頭。
2. (A) ── 藉著酒勁。
3. (A) ── 跌倒當下扭傷腳。
4. (A) ── 在那當下的勁頭下(非深思)。
5. (A) ── 「その場のはずみで」正確。