“〜ga hayai ka”: As Soon As 〜 (immediately upon the action) [JLPT N1]

Content by NTJ Kuma · Nihongo to Japan editorial team · Updated July 27, 2026

「ベルが鳴るが早いか飛び出した」 — the instant one thing happens, the next follows (a literary “as soon as”).

「名前を呼ばれるが早いか、飛び出した」 — the front foot barely moves, the back foot follows

To describe a reaction so fast it's almost simultaneous, 「彼は名前を呼ばれるが早いか、教室を飛び出した」 (the moment his name was called, he dashed out of the classroom) — 「〜が早いか」 = the moment ～, immediately ～, used to express “the first action has barely happened when (almost simultaneously) the next is done at once.” It stresses two actions in tight succession, fast enough to seem simultaneous. This guide covers attachment, the division of labor with 「や否や／とたん／なり,」 and warns of the 「Vのが早い」 ≠ 「Vが早いか」 trap.

Core: the front foot barely moves, the back foot follows — almost simultaneous

「verb dictionary form ＋ が早いか」 means “the first action barely happens when (with no gap) the next is done at once”:

• 子供は母親の顔を見るが早いか、わっと泣き出した (the moment the child saw its mother's face, it burst into tears).
• 犯人は警官の姿を見るが早いか、逃げ出した (the moment the culprit saw the officer, he bolted).
• 彼はベルが鳴るが早いか、教室を飛び出した (the moment the bell rang, he dashed out of the classroom).

Feel: the core is “tight succession, speed” — the first action barely happens when the second follows at once with no gap, fast enough to seem simultaneous. 「が早いか」 literally is “is (saying) the first faster, or (the second)” — so fast you can't tell which came first. It carries a “surprise at the speed” feel, mostly describing others' unexpectedly swift reactions (cried the moment they saw, dashed the moment the bell rang). It corresponds to “the moment ～, (immediately) ～, no sooner ～ than ～.”

How it attaches

See it in context

• 彼は席に着くが早いか、料理をがつがつ食べ始めた。(The moment he sat down, he started wolfing down the food.)
• そのニュースが流れるが早いか、株価が急落した。(The moment that news broke, the stock price plunged.)
• 電車のドアが開くが早いか、乗客がどっと降りてきた。(The moment the train doors opened, passengers poured out.)
• 母の姿を見つけるが早いか、子供は駆け寄った。(The moment the child spotted its mother, it ran over.)
• 彼は横になるが早いか、いびきをかき始めた。(The moment he lay down, he started snoring.)

⚠️ Easy traps to avoid

① Attach the verb dictionary form, not the た-form or て-form. This is the commonest attachment error. Before 「が早いか」 always comes a verb dictionary form, and even if the second half is a past event, the first half stays in the dictionary form (not the た-form): ✗ 着いたが早いか／✗ 着いてが早いか → ✓ 着くが早いか、〜た. Because 「が早いか」 compares the “first action” as an “(almost simultaneous) time point,” the first half uses the dictionary form, and the second half is what actually happens (often た-form). Under the influence of “the second half is past,” learners easily change the first half to た-form too — that's wrong. Mnemonic: (verb dictionary form) が早いか、(second half た-form) = the moment ～, immediately ～.

② 「Vのが早い」 ≠ 「Vが早いか」 — one 「の」 apart, entirely different meanings. This is the easiest confusion. 「verb ＋ のが早い」 = does the action fast (a plain speed description): this is 「〜のが早い,」 a sentence describing speed, meaning “(someone) does some action fast”: 彼は食べるのが早い (he eats fast — describing his eating speed), 決断するのが早い (quick to decide). 「verb ＋ が早いか」 = the moment ～, immediately ～ (two actions in tight succession): this is the lesson's 「〜が早いか,」 “the first action barely happens, then the next follows at once”: 彼は席に着くが早いか、食べ始めた (the moment he sat, he started eating — “sit” and “start eating” in tight succession). Difference: 「のが早い」 is “(doing something) is fast” (the speed of a single action); 「が早いか」 is “the moment ～, immediately ～” (two actions in tight succession). One 「の」 apart, one about speed, one about succession. Test: is there a 「の」 — 「Vのが早い (fast)」 vs 「Vが早いか (the moment ～)」 — don't mix them.

③ Division of labor with 「や否や／とたん／なり.」 These all express “the moment ～,” but differ in feel. 「が早いか」 = the moment ～, immediately ～ (two actions almost simultaneous, surprise at speed, written): 見るが早いか. 「や否や」 = the moment ～, at once ～ (≒ が早いか, written, a touch stiffer): 着くや否や. 「とたん(に)」 = the moment ～ (an instant, often with an unexpected result) (see 〈とたん〉): 立ったとたん、めまいがした (the moment I stood, I felt dizzy — unexpected). 「なり」 = the moment ～, immediately ～ (often with an unexpected／following action or state) (see 〈なり〉): 帰るなり寝てしまった (the moment he got home, he fell asleep). Difference: が早いか／や否や stress “two actions almost simultaneous”; とたん stresses “an instant ＋ an unexpected result”; なり stresses “the moment ～, immediately (an unexpected act).” Test: to stress “front foot moves, back foot follows, almost simultaneous” → が早いか／や否や; “an instant ＋ unexpected” → とたん (see 〈とたん〉); “the moment ～, immediately (an unexpected act)” → なり (see 〈なり〉).

🔄 Nuance & comparison: が早いか／や否や／とたん(に)／なり

💡 How to remember this

「〜が早いか」 = the moment ～, immediately ～ (the front foot barely moves, the back foot follows — almost simultaneous) — three points: ① attach the verb dictionary form — even if the second half is past, the first half stays dictionary form (✗着いたが早いか→✓着くが早いか); ② 「Vのが早い (fast)」 ≠ 「Vが早いか (the moment ～)」, one 「の」 apart, entirely different meanings; ③ division of labor with 「や否や (≒)／とたん (an instant, unexpected, see 〈とたん〉)／なり (the moment ～, immediately, see 〈なり〉).」 This pattern is vivid, mostly describing others' unexpectedly swift reactions — cried the moment they saw, dashed the moment the bell rang, ate the moment they sat. It's a written, narrative register, common in fiction and news. To vividly write “barely ～, and (unexpectedly) at once ～,” 「〜が早いか」 has the most sense of speed.

❓ Quick FAQ

Q: Why is the dictionary form used before 「が早いか」 when the second half is clearly past?

Because 「が早いか」 treats the first action as a “time reference point” for comparing speed, and this structure requires the first half in the dictionary form, even if the whole thing has happened. Its literal logic is “is (saying) the first (happens) faster, or (saying) the second (happens) faster” — the two actions so fast you can't tell the order, so the first half uses the dictionary form as the “comparison baseline,” and the second half is the “actually-following” action (often た-form): 彼は席に着くが早いか、食べ始めた (the moment he sat, he started eating — 「着く」 in dictionary form as baseline, 「食べ始めた」 the actual past action). Learners, influenced by “this has happened (past),” often change the first half to た-form (✗ 着いたが早いか) — that's wrong; the first half is always the dictionary form, and pastness is shown by the second half's た-form. Test: regardless of whether the event is past, before 「が早いか」 always use the dictionary form (見るが早いか, 着くが早いか, 鳴るが早いか), with the second half's た-form for past. Remember this fixed “front dictionary, back た-form” pairing. This differs from 「〜とたん」 — 「とたん」 precedes a た-form (立ったとたん), the exact opposite attachment, so don't mix them (see 〈とたん〉).

Q: 「が早いか,」 「や否や,」 「とたん,」 「なり」 all mean ‘the moment ～' — how do I choose?

All four express “the moment ～,” but each has its emphasis, told apart by “simultaneity, unexpectedness, the nature of the second half.” ① 「が早いか」 = the moment ～, immediately ～ (two actions almost simultaneous, surprise at speed): stresses “front foot barely moves, back foot follows, almost simultaneous,” mostly describing others' unexpectedly swift reactions: 警官を見るが早いか、逃げ出した (bolted the moment he saw the officer). Attaches to the dictionary form. ② 「や否や」 ≒ 「が早いか」 (written, a touch stiffer): 着くや否や、電話した (called the moment he arrived). Attaches to the dictionary form, feel almost identical to が早いか, more written. ③ 「とたん(に)」 = the moment ～ (an instant, often with an unexpected result): stresses “at that instant, (unexpectedly) something happened,” the second half often an unexpected, non-volitional result: 立ったとたん、めまいがした (the moment I stood, I felt dizzy — an unexpected physical reaction). Attaches to the た-form (see 〈とたん〉). ④ 「なり」 = the moment ～, immediately ～ (often with an unexpected or following action／state, the subject often staying in that state): 帰るなり、部屋に閉じこもった (the moment he got home, he shut himself in his room). Attaches to the dictionary form (see 〈なり〉). Simply: stress “almost simultaneous” → が早いか／や否や (dictionary form); stress “an instant ＋ unexpected result” → とたん (た-form); stress “the moment ～, immediately (an unexpected act)” → なり (dictionary form). Of these, 「が早いか」 and 「や否や」 lean “two tightly-succeeding actions,” 「とたん」 leans “an instant's unexpected change,” 「なり」 leans “finish one, immediately follow with another.” In practice が早いか and や否や are closest (interchangeable), and とたん's attachment (た-form) differs from the other three, making it the easiest to distinguish.

🖊️ Practice Questions (5)

Q1. 「子供は母親の顔を見る___、泣き出した。」(started crying the moment they saw)

(A) が早いか　(B) が遅いか　(C) からして　(D) どころか

Q2. 「が早いか」の前に来る動詞の形は?

(A) Dictionary form　(B) た形　(C) ない形　(D) て形

Q3. 「ベルが鳴るが早いか飛び出した」の意味は?

(A) Dashes out the instant the bell rings

(B) Goes out long after the bell rings

(C) Didn't hear the bell

(D) The bell didn't ring

Q4. 「が早いか」の後件として不適切なのは?

(A) Command / negative (cannot attach)

(B) A swift past action

(C) An action that occurs immediately after

(D) An unexpectedly fast action

Q5. 接法が正しいのは?

(A) 着くが早いか、寝てしまった。　(B) 着いたが早いか。

(C) 着くが早いか、寝なさい(command)。　(D) 着いてが早いか。

Answer Explanations

1. (A) が早いか ── Bursts into tears the instant they see.

2. (A) Dictionary form ── Dictionary form ＋ が早いか.

3. (A) ── Dashes out the instant the bell rings.

4. (A) ── The main clause doesn't take a command/negative.

5. (A) ── 「着くが早いか、寝てしまった」is correct.