べからず

A classical Japanese construction combining べき (should) with the classical negative ず. Though archaic in normal conversation, it remains alive in modern Japanese through signs, rules, and proverbs.

Common patterns

Attaches to the dictionary form (終止形(しゅうしけい)) of verbs:

• 入(はい)るべからず (must not enter)
• 忘(わす)るべからず (must not forget — uses the classical 終止形(しゅうしけい) of 忘(わす)れる)
• するべからず (must not do)

Common set phrases

• 初心(しょしん)忘(わす)るべからず: never forget the beginner's spirit (famous saying attributed to Zeami)
• 侮(あなど)るべからず: not to be underestimated
• 関係者以外(かんけいしゃいがい)立(た)ち入(い)るべからず: no entry except for authorized personnel

Usage

In modern Japanese, べからず appears mainly in:

• Prohibition signs and notices
• Proverbs and maxims
• Formal rules and regulations
• Literary or deliberately archaic writing

Similar words

• てはいけない: must not — the standard modern equivalent
• てはならない: must not — more formal modern equivalent
• 禁止(きんし): prohibited — a noun used on signs