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べからず

Must not / Shall not / Is strictly prohibited

This grammar expresses that an action is forbidden without exception, often based on law, rules, ethics, or principles. (an absolute, rule-based prohibition)

N1

Meaning

Must not / Shall not / Is strictly prohibited

This grammar expresses that an action is forbidden without exception, often based on law, rules, ethics, or principles. (an absolute, rule-based prohibition)

Formation

Verb (dictionary form) + べからず

Explanation

べからず is a classical and very formal negative obligation meaning “must not do.”

Core idea:

  • “This action is not allowed”

  • “This must never be done”

  • “This violates rules or principles”

Important nuance:

  • Stronger and more absolute than ～てはいけない

  • Sounds authoritative, rigid, and rule-oriented

  • Leaves no room for personal judgment or exception

This grammar is commonly found in:

  • laws and regulations

  • official notices

  • moral or ethical codes

  • historical or literary texts

  • JLPT N1 reading passages

It is rare in modern spoken Japanese.