ず / ぬ / ざる: Classical Negation | Japanese Grammar

Modern Japanese negates with ない — 行かない, 食べない. But ない is a relative newcomer, and it never fully evicted its predecessor. The classical negative auxiliary ず is still lodged across everyday Japanese in a scatter of forms — ず, ぬ, ね, ざる — that look unrelated until you realize they are one auxiliary conjugating through its paradigm. やむを得（え）ず, 思（おも）わず, 相変（あいか）わらず, 見（み）ず知（し）らず, the exam-frequency 〜ざるを得ない: every one is the same ず, in a different slot of the same table. Learn to read ず／ぬ／ざる／ね as nothing more exotic than "not," and dozens of fixed expressions decode in a single stroke. This page is N1 material precisely because these fossils are unavoidable — they turn up in ordinary polite speech, not just old texts.

One auxiliary, two rows

ず attaches to the 未然形（みぜんけい, the irrealis stem） — the same stem modern ない attaches to. Its conjugation runs in two rows, and understanding why there are two is the key to the whole system.

	未然形	連用形	終止形	連体形	已然形	命令形
ず row	ず	ず	ず	ぬ	ね	—
ざり row (ず＋あり)	ざら	ざり	—	ざる	ざれ	ざれ

The ず row handles the core jobs: 連用ず ("not …-ing, without …"), 終止ず (ending a sentence "does not"), 連体ぬ (before a noun), 已然ね (with ば). The ざり row exists for one reason: it is ず fused with あり（"to exist"）, and that あり lets the negative carry a further auxiliary. ず alone cannot take a past or conjectural ending, but ざり can — 及（およ）ばざりけり "did not reach" (ざり＋ past けり). So ざる and ざれ are not a separate word; they are ず reaching for extra grammar.

💡

Do not memorize ず, ぬ, ね, ざる, ざれ as five vocabulary items. They are one negative — "not" — in five grammatical slots. The moment you read all of them as ない, the fossils that use them stop being cryptic and start being obvious.

ず attaches to the 未然形

The attachment rule is identical to modern ない: take the verb's 未然形 and add ず.

Verb	未然形	＋ず	Modern
知る	知ら	知らず	知らない
及ぶ	及ば	及ばず	及ばない
する（サ変）	せ	せず	しない
来る（カ変）	こ	来ず（こず）	来ない

Note the irregulars: サ変する gives せず（not ×しず）and カ変来る gives 来ず＝こず（not ×きず）. These trip up learners because the modern verb hides the classical 未然形.

やむを得ず遅刻しました。

yamu o ezu chikoku shimashita

I was late, and it couldn't be helped. (やむを得ず = 得 + classical ず — ordinary polite speech, not archaic at all)

何も言わずに帰ってしまった。

nani mo iwazu ni kaette shimatta

He went home without saying a word. (連用形ず + に = 'without doing', the everyday 〜ずに)

That last pattern, 〜ずに, is the living heir of the 連用形ず: "without doing X." It is fully current in writing and careful speech.

The 連体形ぬ: before a noun

Before a noun, the negative is ぬ, not ない. This is the form frozen into countless set phrases.

知らぬ間に日が暮れていた。

shiranu ma ni hi ga kurete ita

Before I knew it, night had fallen. (知らぬ間に = 'while not knowing / before one realizes')

見ず知らずの人に道を尋ねた。

mizu shirazu no hito ni michi o tazuneta

I asked directions of a complete stranger. (見ず知らず = 'neither seen nor known' — two ず in one fixed phrase)

思わず声を上げてしまった。

omowazu koe o agete shimatta

I let out a cry in spite of myself. (思わず = 'without thinking', a high-frequency adverb built on ず)

思わず, 我（われ）知らず, 心ならずも — the "involuntarily / in spite of oneself" family — are all ず fossils. So is the 〜ぬ間に frame that means "before / while not yet."

The ざる row: 〜ざるを得ない

The most important survival for exam-takers is 〜ざるを得（え）ない, "cannot help but / have no choice but to." It is the ざる連体形 modifying を得ない ("cannot obtain [not doing it]" → "cannot avoid doing it").

事実だと認めざるを得ない。

jijitsu da to mitomezaru o enai

I have no choice but to admit it's a fact. (認め + ざる + を得ない — the standard N2/N1 pattern)

この結果には満足せざるを得ない。

kono kekka ni wa manzoku sezaru o enai

I can't help being satisfied with this result. (satisfy = 満足する → せ + ざる, the サ変 irregular)

The literal logic is worth seeing: 認めざる＝ "not admitting," を得ない＝ "cannot get/obtain" — "one cannot obtain not-admitting," i.e. there is no way to avoid admitting. That is why the pattern demands ざる and nothing else: the whole idiom is a classical negative wrapped inside a classical "cannot."

The 已然形ね: 〜ねばならない

The 已然形ね survives in the formal obligation frame 〜ねばならない（"must, cannot not"）— ね＋ば＝ classical "if not," plus ならない "won't do":

明日までに終わらせねばならない。

ashita made ni owaraseneba naranai

I have to get it finished by tomorrow. (終わらせ + ね + ば + ならない — the 已然形ね, still standard in formal speech)

行かねばならぬ, 言わねばなるまい — the whole "must" register in formal Japanese runs on this ね. It sits one step up from casual 〜なきゃ but is entirely current in speeches, writing, and workplace formality.

Why you cannot swap in ない

Here is the point competing resources miss. These are not free variants where you may use classical ず or modern ない as you please. The fossils are frozen with their classical inflection, and substituting ない breaks them.

絶えず努力を続けている。

taezu doryoku o tsuzukete iru

She keeps up a constant effort. (絶えず = 'without ceasing'; there is no ×絶えないで here)

彼は相変わらず忙しそうだ。

kare wa aikawarazu isogashisō da

He seems as busy as ever. (相変わらず is a fixed adverb — no ×相変わらないで exists)

その一言に少なからず驚いた。

sono hitokoto ni sukunakarazu odoroita

That remark surprised me not a little. (少なからず = 少なし + ず, 'not a little' = considerably)

Try to "modernize" any of these and the word simply ceases to exist: there is no 絶えないで, no 相変わらないで, no 少なくなく in these slots. The classical ず is load-bearing — the fixed phrase demands its classical inflection, exactly as an English fossil demands "cannot help but," not "cannot help however."

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The diagnostic: if replacing ず／ぬ／ざる with a modern ない form produces something no one would say, you are holding a fossil, and the classical form is mandatory. やむを得ず, 思わず, 相変わらず, 〜ざるを得ない — none of them survive translation into ない.

Common mistakes

❌ やむを得ないで遅刻した。

yamu o enaide chikoku shita

Wrong — trying to build the adverb from modern 得ない + で. The fixed adverbial form is やむを得ず.

✅ やむを得ず遅刻した。

yamu o ezu chikoku shita

I was late, unavoidably. (the frozen adverb keeps classical ず; there is no やむを得ないで in this slot)

やむを得ず is a fossilized 連用形. The modern 得ないで does exist as a phrase elsewhere, but it cannot replace the fixed adverb here.

❌ 認めないを得ない。

mitomenai o enai

Wrong — plugging modern 認めない into the 〜を得ない frame. The frame requires the classical 連体形ざる.

✅ 認めざるを得ない。

mitomezaru o enai

I have no choice but to admit it. (the pattern is 未然形 + ざる + を得ない, never ない + を得ない)

The 〜ざるを得ない construction is built on classical ざる. A modern ない cannot slot into it — the idiom would collapse.

❌ しず／きず

shizu / kizu

Wrong stems — negating する and 来る by analogy with the dictionary form. The 未然形 is irregular.

✅ せず／来ず（こず）

sezu / kozu

does not do / does not come (サ変 → せ + ず; カ変 → こ + ず — the classical irregular stems)

ず attaches to the 未然形, and する／来る have irregular 未然形せ／こ. 勉強せず, 帰らず来ず — get the stem right.

❌ 見ないで知らない人。

minaide shiranai hito

Wrong — 'modernizing' the set phrase 見ず知らず into a modern paraphrase, losing the idiom.

✅ 見ず知らずの人。

mizu shirazu no hito

a total stranger (the fixed compound stacks two classical ず; it has no modern-ない equivalent)

Set compounds like 見ず知らず are single frozen words. Paraphrasing them into ない forms produces something grammatical but not the idiom.

Key takeaways

ず, ぬ, ね, ざる, ざれ are one classical negative auxiliary — "not" — conjugating through its paradigm, not five separate words.
ず attaches to the 未然形（知ら＋ず）, with irregular せず（する）and 来ず＝こず（来る）.
The ず row does the core work (連用ず, 終止ず, 連体ぬ, 已然ね); the ざり row（ざら／ざり／ざる／ざれ）is ず＋あり, existing to carry further auxiliaries.
Everyday survivals span every slot: やむを得ず, 思わず, 〜ずに（連用）, 知らぬ間に, 見ず知らず（連体ぬ）, 〜ざるを得ない（連体ざる）, 〜ねばならない（已然ね）, plus 絶えず, 相変わらず, 少なからず.
The classical form is mandatory in these fossils — swapping in modern ない（×やむを得ないで, ×認めないを得ない）breaks the fixed phrase.

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