Japanese by Example
Learning through examples in manga

Doing as you please is strictly forbidden with 〜べからず

Manga panel from くノ一ツバキの胸の内 showing example of Doing as you please is strictly forbidden with 〜べからず.
くノ一ツバキの胸の内 » Volume 1 » Page 106

Sazanka sneaks out of class, leaving the teacher to send Asagao to bring her back. As Asagao chases Sazanka across the rooftops near the upper grade classroom, Tsubaki spots them. She meets them up on the roof and recites the school’s first rule.

ツバキ:
「ひとつ。無断(むだん)勝手(かって)行動(こうどう)をとるべからず。」
“One: Doing as you please without permission is strictly forbidden.”

Key Points

  1. べからず = “must not / is strictly forbidden”
    • Here とるべからず gives the line the feel of an official rule: “must not take such action” / “is strictly forbidden”
    • Pattern: [verb dictionary form] + べからず → “must not [verb]”
    • A natural modern paraphrase here is 無断(むだん)勝手(かって)行動(こうどう)をとってはいけない
  2. What is being forbidden: 無断(むだん)勝手(かって)行動(こうどう)をとる
    • The whole phrase before べからず describes the prohibited behavior: taking self-directed action without permission
    • 無断(むだん) = “without permission, without authorization”
    • 勝手(かって)行動(こうどう) = “self-willed / arbitrary behavior”; not just any action, but acting on your own judgment
  3. Sentence anatomy: [無断(むだん)で] [勝手(かって)行動(こうどう)] をとる
    • 無断(むだん) modifies how the action is done, while 勝手(かって) modifies 行動(こうどう)
    • A simplified core is 行動(こうどう)をとる → “to take action / engage in behavior”
    • So the line builds from the noun phrase outward: unauthorized + self-directed + action
  4. Formal rule-book tone: ひとつ。〜べからず。
    • ひとつ。 introduces item one in a formal list of rules or precepts
    • Together with べからず, it makes Tsubaki sound like she is reciting a fixed code rather than speaking casually
    • That stiff, old-fashioned style matches the school-rule atmosphere of the scene