べからず / べからざるbekarazu / bekarazaru“must not; should not; do not”

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 ~

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”.

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, 来る(くる) becomes 来(く)べからず
• べからざる: Dictionary form of verb + べからざる (acts as a prenominal modifier)
  → 許す(ゆるす)べからざる, 犯す(おかす)べからざる

Note that べからざる is an archaic attributive form of べからず and is always followed by a noun.

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

• ここで釣り(つり)をすべからず。
  No fishing here. (sign)

• 無断(むだん)で立ち入る(たちいる)べからず。
  Unauthorized entry is forbidden.

• それこそ許す(ゆるす)べからざる行為(こうい)だ。
  That is an unforgivable act.

• 人(ひと)として犯す(おかす)べからざる罪(つみ)だ。
  It is a sin one must never commit as a human being.

• この機会(きかい)を逃す(のがす)べからずと思っ(おもっ)た。
  I thought this opportunity must not be missed.

• 君子(くんし)は危(あや)うきに近づく(ちかづく)べからず。
  A gentleman must not put himself in harm’s way. (proverb)

After reading each sentence, ask what job べからず / べからざる is doing: strong prohibition or an absolute denial.

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.

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:

• ここに入る(はいる)べからず。 (Sign — absolute, impersonal)
• ここに入る(はいる)べきではない。 (Advice — subjective, personal)

Is the sentence a rule carved in stone, or a friend’s recommendation?

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

Practice questions for べからず / べからざる

• 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.

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 来る(くる).
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 — 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 — because it also deals with the point of no return and irreversible consequences
• べくもない — because it is the negative potential form of べく and carries a similar archaic weight
• ばこそ — 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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