# べからず / べからざる: must not; should not; do not ~

> Learn how to use べからず / べからざる, a JLPT N1 Japanese grammar point meaning must not, with structure, nuance, examples, mistakes, and comparisons.

JLPT level: N1 · Updated: 2026-05-18 · Canonical: https://hane-app.com/blog/n1-bekarazu-bekarazaru/

**べからず / べからざる** means **must not; should not; do not ~**. It is a **JLPT N1** Japanese grammar pattern used to express strong prohibition or an absolute denial, often in formal writing and idiomatic expressions.

This grammar point often appears in legal texts, signs, formal admonitions, and JLPT N1 reading passages. If you want to express strong prohibition or an absolute denial, **べからず / べからざる** is a useful pattern to learn because it adds a formal, authoritative tone to your Japanese.

## What does べからず / べからざる mean?

Use **べからず / べからざる** when you want to express strong prohibition or an absolute denial.

Natural translations include:
- must not; should not; do not ~

The best translation depends on the sentence. **べからず** is a sentence-ending prohibition, while **べからざる** is an attributive form that modifies a noun, like “unforgivable” or “impermissible”. Try to notice the writer's or speaker's purpose first, then choose the English phrase that fits that context.

## How to form べからず / べからざる

- **べからず**: Dictionary form of verb + べからず  
  → する becomes すべからず, <ruby>来る<rp>(</rp><rt>くる</rt><rp>)</rp></ruby> becomes <ruby>来<rp>(</rp><rt>く</rt><rp>)</rp></ruby>べからず
- **べからざる**: Dictionary form of verb + べからざる (acts as a prenominal modifier)  
  → <ruby>許す<rp>(</rp><rt>ゆるす</rt><rp>)</rp></ruby>べからざる, <ruby>犯す<rp>(</rp><rt>おかす</rt><rp>)</rp></ruby>べからざる

<div class="formation">
  <span class="ftoken t-stem"><ruby>動詞<rp>(</rp><rt>どうし</rt><rp>)</rp></ruby><br/>(<ruby>辞書<rp>(</rp><rt>じしょ</rt><rp>)</rp></ruby><ruby>形<rp>(</rp><rt>けい</rt><rp>)</rp></ruby>)</span>
  <span class="fplus">＋</span>
  <span class="ftoken t-aux">べからず</span>
</div>

<div class="formula">する → すべからず / <ruby>来る<rp>(</rp><rt>くる</rt><rp>)</rp></ruby> → <ruby>来<rp>(</rp><rt>き</rt><rp>)</rp></ruby>べからず</div>

The form before the grammar point matters. Note that **べからざる** is an archaic attributive form of **べからず** and is always followed by a noun. In JLPT questions, the wrong answer choices often use a similar meaning but attach it to the wrong type of word.

## When is べからず / べからざる used?

Use **べからず / べからざる** in situations like:
- issuing a formal prohibition (signs, rules, legal texts)
- stating an unbreakable moral or natural law
- modifying a noun to describe something utterly unacceptable

Tone and register:
- very formal, literary, or archaic; common in old‑fashioned rules, proverbs, and academic writing
- Common in test questions, formal essays, and JLPT N1 reading

## べからず / べからざる example sentences

- ここで<ruby>釣り<rp>(</rp><rt>つり</rt><rp>)</rp></ruby>を<b>すべからず</b>。  
  <em>No fishing here. (sign)</em>

- <ruby>無断<rp>(</rp><rt>むだん</rt><rp>)</rp></ruby>で<ruby>立ち入る<rp>(</rp><rt>たちいる</rt><rp>)</rp></ruby><b>べからず</b>。  
  <em>Unauthorized entry is forbidden.</em>

- それこそ<b><ruby>許す<rp>(</rp><rt>ゆるす</rt><rp>)</rp></ruby>べからざる</b><ruby>行為<rp>(</rp><rt>こうい</rt><rp>)</rp></ruby>だ。  
  <em>That is an unforgivable act.</em>

- <ruby>人<rp>(</rp><rt>ひと</rt><rp>)</rp></ruby>として<b><ruby>犯す<rp>(</rp><rt>おかす</rt><rp>)</rp></ruby>べからざる</b><ruby>罪<rp>(</rp><rt>つみ</rt><rp>)</rp></ruby>だ。  
  <em>It is a sin one must never commit as a human being.</em>

- この<ruby>機会<rp>(</rp><rt>きかい</rt><rp>)</rp></ruby>を<b><ruby>逃す<rp>(</rp><rt>のがす</rt><rp>)</rp></ruby>べからず</b>と<ruby>思っ<rp>(</rp><rt>おもっ</rt><rp>)</rp></ruby>た。  
  <em>I thought this opportunity must not be missed.</em>

- <ruby>君子<rp>(</rp><rt>くんし</rt><rp>)</rp></ruby>は<ruby>危<rp>(</rp><rt>あや</rt><rp>)</rp></ruby>うきに<b><ruby>近づく<rp>(</rp><rt>ちかづく</rt><rp>)</rp></ruby>べからず</b>。  
  <em>A gentleman must not put himself in harm's way. (proverb)</em>

After reading each sentence, ask what job **べからず / べからざる** is doing: strong prohibition or an absolute denial. That makes the nuance easier to remember than a one-word translation.

## Nuance of べからず / べからざる

The key nuance is **strong prohibition or an absolute denial, often with a formal, archaic, or moralistic weight**.

This matters because learners often translate advanced grammar too literally. A pattern may look simple, but it can signal the writer's attitude, the scope of a rule, or the relationship between two ideas.

For example:
- Using **べからず** instead of **てはいけない** instantly changes the register from casual to authoritarian or legalistic.
- When you use **べからざる** before a noun, you emphasize that the quality is so severe it *must not* exist, not just *should not*.

## べからず / べからざる vs べきではない

Both **べからず / べからざる** and **べきではない** can express “should not”, but they are different.

**べからず / べからざる**:
- expresses an absolute, often impersonal prohibition; formal/literary tone

**べきではない**:
- expresses a softer, personal judgment about what should not be done; neutral/colloquial tone

Quick contrast examples:
- ここに<ruby>入る<rp>(</rp><rt>はいる</rt><rp>)</rp></ruby><b>べからず</b>。 (Sign — absolute, impersonal)
- ここに<ruby>入る<rp>(</rp><rt>はいる</rt><rp>)</rp></ruby><b>べきではない</b>。 (Advice — subjective, personal)

If both translations seem possible, check the tone. Is the sentence a rule carved in stone, or a friend's recommendation? The tone often tells you which grammar point is natural.

## Common mistakes with べからず / べからざる

Watch out for these mistakes:
- Using **べからず** in casual conversation where it sounds laughably old‑fashioned.
- Confusing the attributive form **べからざる** with the sentence-final **べからず**.
- Adding だ after べからず (it is already a complete predicate).

A helpful practice method is to take a rule you see on a sign (e.g. “No smoking”), write the official‑sounding **べからず** version, then rewrite it as ordinary advice with **べきではない** or **てはいけない**. Notice how the gravity shifts.

## Is べからず / べからざる on the JLPT?

Yes. **べからず / べからざる** is commonly taught as **JLPT N1** grammar.

That means learners should be able to:
- recognize it in reading, especially in formal or historical contexts
- understand its nuance as an absolute prohibition
- identify the attributive form **べからざる** modifying a noun

For test preparation, study the grammar point in full sentences. JLPT questions often test whether you understand the surrounding context, not just the dictionary meaning.

## Practice questions for べからず / べからざる

Try making your own sentences with these prompts:
- Write a short, official rule using **べからず** (e.g., a library sign).
- Use **べからざる** to describe a behaviour you find utterly unacceptable.
- Compare a sentence with **べからず** and one with **べきではない** to show the nuance difference.

Keep your first sentences simple. Once the structure feels natural, add more context so the nuance becomes clear.

## Learning path for べからず / べからざる

To learn **べからず / べからざる** efficiently, start with its formation, then compare it with similar patterns, and finally practice in context.

1. First, make sure you can form **べからず** and **べからざる** from any dictionary-form verb, including する and <ruby>来る<rp>(</rp><rt>くる</rt><rp>)</rp></ruby>.
2. Next, compare it with **べきではない**. These patterns are close enough that choosing between them helps you understand the nuance of formality and absoluteness.
3. Finally, find examples in real‑life Japanese (rules, classic literature) and rewrite them using modern prohibitions to feel the stylistic shift.

## Related grammar to review next

- [べく](/blog/n1-beku/) — because it also comes from the auxiliary べし and expresses purpose or intention
- [ば〜それまでだ / たらそれまでだ](/blog/n1-ba-sore-made-da-tara-sore-made-da/) — because it also deals with the point of no return and irreversible consequences
- [べくもない](/blog/n1-beku-mo-nai/) — because it is the negative potential form of べく and carries a similar archaic weight
- [ばこそ](/blog/n1-ba-koso/) — because it also uses a conjunctive form to emphasize an exclusive reason

## Learn べからず / べからざる with Hane

If you want to review **べからず / べからざる** together with the related patterns above, Hane helps you practice Japanese in short, focused sessions.

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