“〜ya inaya”: The Moment 〜, Immediately 〜 (Instantaneous Sequence) [JLPT N1]

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

「席に着くやいなや話し始めた」 — the instant one thing happens, the next is already underway.

「ベルが鳴るやいなや、教室を飛び出した」 — the bell rang and out they dashed

To depict two things happening almost at once, one hard on the heels of the other, written Japanese uses an instantaneous connective — 「彼はその知らせを聞くやいなや、駆け出した (he heard the news and dashed off).」 「〜やいなや」 = the instant ～, no sooner ～ than. It's a written, somewhat stiff instantaneous connective. This guide clarifies its core of “two acts hard on each other,” separating it from the also-“the instant ～” 「が早いか」「なり」「とたん.」

Core: the instant ～, no sooner ～ than (two acts almost at once, hard on each other)

「verb dictionary form ＋ やいなや」 means “the instant ～, no sooner ～ than” — the first act happens, and the second follows almost at once, hard on its heels:

• ベルが鳴るやいなや、生徒たちは教室を飛び出した (the instant the bell rang, the students dashed out of the classroom).
• 彼は席に着くやいなや、話し始めた (the instant he sat down, he began to talk).
• その一報が届くやいなや、株価は暴落した (the instant that report arrived, the stock crashed).

Feel: the core is “the first act happens, the second follows almost at once, hard on its heels,” the two with almost no time gap. It leans written, stiff, more objectively narrating “the instant ～, ～,” common in fiction, news. 「や否や（やいなや）」's literal comes from the classical “や (once ～) ＋ 否や (whether not yet ～)” = “(the first) barely done or not, (the second) already ～,” hence extended to “no sooner ～ than.” In English: “the instant ～, no sooner ～ than, the moment ～.”

Forms & attachment

Examples in use

• ドアが開くやいなや、子供たちが飛び込んできた。(The instant the door opened, the children rushed in.)
• 彼女は手紙を読み終えるやいなや、泣き崩れた。(The instant she finished reading the letter, she broke down in tears.)
• 号砲が鳴るやいなや、選手たちは一斉に走り出した。(The instant the starting gun fired, the runners all set off.)
• その提案が出されるや否や、会場は騒然となった。(No sooner was the proposal made than the venue turned to uproar.)
• 彼は帰宅するやいなや、ベッドに倒れ込んだ。(The instant he got home, he collapsed onto the bed.)

⚠️ Common mistakes to avoid

① The core is ‘the first happens, the second follows almost at once,' leaning written, stiff. This is 「やいなや」's core feel. It means “the first act happens, the second follows almost at once, immediately hard on its heels” — the two with almost no time gap: ベルが鳴るやいなや飛び出した (the bell rang and out they dashed — “bell rings” and “dash out” almost simultaneous). It leans written, somewhat stiff, solemn, more objectively narrating the two acts' adjacency, common in fiction, news, formal narration, little used in everyday speech (spoken “the instant ～” uses 「〜たらすぐ」). Test: to narrate in writing “the instant ～, no sooner ～ than” → やいなや.

② Attachment: verb dictionary form ＋ やいなや. In attachment, 「やいなや」 precedes a verb dictionary form (鳴る→鳴るやいなや, 着く→着くやいなや), not the た-form. 「や否や」 is a synonymous kanji spelling (same reading). Test: verb dictionary form ＋ やいなや (鳴るやいなや).

③ Separate it from 「が早いか」 — both ‘no sooner ～ than,' が早いか carries a bit of urgency／can't-wait. This is the closest pair. 「〜やいなや」 = the instant ～ (written, stiff, objectively narrating the two acts' adjacency): 着くやいなや、電話をかけた (the instant I arrived, I made a call — objectively narrating adjacency). It's more objective, written. 「〜が早いか」 = the instant ～ (see 〈が早いか〉, with a bit of ‘can't wait, impatient' feel): ベルが鳴るが早いか、飛び出した (the bell rang and (impatiently) out they dashed — with a bit of “can't wait” urgency). It carries a bit of “doing the second impatiently, almost before the first is fully over.” The difference is small: 「やいなや」 more objectively, in writing, narrates adjacency; 「が早いか」 carries a bit of urgency, can't-wait (see 〈が早いか〉). Test: for objective, written “the instant ～” → やいなや; for a bit of “can't wait” → が早いか. (They mostly interchange.)

④ Separate it from 「なり」「とたん」 — なり leans a third person's sudden reaction, とたん carries surprise. These all express “the instant ～,” but differ in emphasis. 「〜やいなや」 = the instant ～ (written, objectively narrating the two acts' adjacency): 鳴るやいなや飛び出した. 「〜なり」 = the instant ～ (see 〈なり〉, mostly narrating a third person's sudden, involuntary reaction): 彼は私を見るなり、逃げ出した (the instant he saw me, he fled — a third person's sudden reaction). 「〜たとたん」 = just as ～ (see 〈とたん〉, with surprise, the unexpected): ドアを開けたとたん、猫が飛び出した (just as I opened the door, the cat (unexpectedly) dashed out — with surprise). Difference: 「やいなや」 = objectively narrating adjacency (written); 「なり」 = a third person's sudden reaction (dictionary form, see 〈なり〉); 「とたん」 = a surprising instant (た-form, see 〈とたん〉). Test: for objective, written “the instant ～” → やいなや; for a third person's sudden reaction → なり; for surprise → とたん. (There's also 「そばから = no sooner ～ than again, repeated futility, see 〈そばから〉.)

🔄 Compare with similar forms: やいなや／が早いか／なり／たとたん

💡 The one thing to remember

「〜やいなや」 = the instant ～, no sooner ～ than — three points: ① the core is ‘the first happens, the second follows almost at once,' leaning written, stiff, objective (鳴るやいなや飛び出した); ② attachment is verb dictionary form ＋ やいなや (や否や synonymous); ③ separate it from the “instant” family — が早いか (a bit of can't-wait, see 〈が早いか〉), なり (a third person's sudden reaction, see 〈なり〉), とたん (surprise, see 〈とたん〉), そばから (repeated futility, see 〈そばから〉). This pattern is a weapon of fiction, news for narrating “two things happening hard on each other” — 「知らせを聞くやいなや駆け出した」 renders, crisply, that tightness of “no sooner ～ than ～.” Japanese has a big “the instant ～” family; やいなや is the most written, most objective of them; for spoken “the instant ～,” 「〜たらすぐ」 is more natural.

❓ Common questions

Q: What's the difference between 「やいなや」 and 「が早いか」? Both ‘no sooner ～ than'?

The two are very close (both the instantaneous “the instant ～”), the difference subtle, in ‘feel.' 「〜やいなや」 = the instant ～ (objectively, in writing, narrating the two acts' adjacency): it's more objective, neutral, written, just plainly narrating “the first happens, the second follows almost at once, hard on its heels,” without special emotion: ベルが鳴るやいなや、皆立ち上がった (the instant the bell rang, everyone stood up — objectively narrating adjacency). 「〜が早いか」 = the instant ～ (with a bit of ‘can't wait, impatient' feel, see 〈が早いか〉): it carries a bit of “doing the second impatiently, almost before the first is fully over” — urgency, eagerness — as if the second's doer “can't wait”: ベルが鳴るが早いか、教室を飛び出した (the bell rang and (impatiently) out of the classroom they dashed — with “can't wait” urgency). The difference (subtle): 「やいなや」 more objective, neutral (just narrating adjacency); 「が早いか」 carries a bit of can't-wait, eager feel (as if can't wait, see 〈が早いか〉). They interchange in many cases, both “no sooner ～ than.” Test: to objectively, in writing narrate “the instant ～, hard on it” → やいなや; for a bit of “can't wait, impatience” → が早いか. These are very close instantaneous connectives, differing mainly in が早いか's extra touch of urgency.

Q: What's the difference between 「やいなや」 and 「とたん」?

The difference is ‘attachment, emphasis.' 「〜やいなや」 = the instant ～ (dictionary form, objectively narrating adjacency, written): it takes a verb dictionary form (鳴るやいなや), more objective, written, just narrating “the first happens, the second follows hard on it,” without special surprise: 号砲が鳴るやいなや、走り出した (the instant the gun fired, they ran off — objective adjacency). 「〜たとたん」 = just as ～ (verb た-form, with surprise, the unexpected, see 〈とたん〉): it takes a verb た-form (開けたとたん), its core carrying the feel “surprise, the unexpected” — “right at the instant of ～, (unexpectedly) something happened”: ドアを開けたとたん、水があふれ出した (just as I opened the door, water (unexpectedly) gushed out — with surprise). Difference: 「やいなや」 = objectively narrating adjacency (dictionary form, written, no surprise); 「とたん」 = a surprising instant (た-form, see 〈とたん〉). Test: for objective, written “the instant ～, hard on it” (no surprise) → やいなや (dictionary form); for “right at the instant of ～, unexpectedly ～” (with surprise) → とたん (た-form). Also, attachment differs: やいなや takes the dictionary form (鳴るやいなや), とたん the た-form (開けたとたん) — don't mix them. So objectively narrating “the bell rang and they ran” uses 「鳴るやいなや,」 the surprising “just as I opened the door, water gushed out” uses 「開けたとたん.」

🖊️ Practice Quiz

Q1. 「彼女の名前を呼ぶ___、振り返った。」(the moment I called her name, she turned around)

(A) たとたん　(B) やいなや　(C) たが最後　(D) てから

Q2. 「信号が青になる___、車が走り出した。」(the moment the light turned green, the cars started off)

(A) やいなや　(B) たが最後　(C) ながらに　(D) どころか

Q3. What's the difference between 「やいなや」 and 「たとたん」?

(A) exactly the same

(B) やいなや allows different subjects before/after; たとたん usually has the same subject

(C) やいなや is negative only; たとたん affirmative only

(D) たとたん is written-only

Q4. 「飛行機が着陸する___、乗客たちは立ち上がった。」(the moment the plane landed, the passengers stood up)

(A) たが最後　(B) やいなや　(C) どころか　(D) ながら

Q5. What's the defining feature of 「やいなや」?

(A) A finishes, then long after, B happens

(B) B happens almost simultaneously with A (an extremely short time gap)

(C) B is a bad result caused by A

(D) A and B are unrelated

Answer Key

1. (B) やいなや ── 名前を呼ぶやいなや、振り返った = the moment I called her name, she turned (instantaneous sequence).

2. (A) やいなや ── 信号が青になるやいなや、車が走り出した (the moment it turned green).

3. (B) ── やいなや allows different subjects before/after; たとたん usually has the same subject.

4. (B) やいなや ── 着陸するやいなや (the moment it landed).

5. (B) ── B happens almost simultaneously with A (an extremely short time gap).