Alternative spelling
可し (obsolete)

From Old Japanese. First attested in the Kojiki of 712 CE.[1]



べし (-beshi

  1. (attaching to terminal form) must, shall
    Antonym: まじ (maji)
    1. indicating certainty
      Chihō rosen no ikutsuka wa yagate haishisarerubeki unmei ni aru.
      Some of the local railways will soon be abolished.
    2. indicating requirement
      Kono ken ni tsuite wa kimi ga sekinin o torubeki da.
      You should take responsibility on this.
      Ashita wa hachiji made ni shukkin-subeshi.
      You should work until eight o'clock tomorrow.
      Eigo wa koe o dashite yomu beki da.
      You should read English aloud.
      Rainen no hakurankai kaisai ni ma ni awaseru beku, tokkan kōji ga okonawareteiru.
      In order to hold the exhibition in time next year, hasty construction is underway.

Usage notesEdit

  • This word is morphologically a clitic. It is classified as 助動詞 (jodōshi, auxiliary verb) in traditional Japanese grammar. Syntactically, it is essentially a verb suffix, attaching only to the terminal or predicative form of the verb rather than to any of the other conjugation stems.
  • The verb する (suru, to do) takes the classical terminal form (su), rather than the modern terminal form する (suru), when preceding べし (beshi). Hence "すべし (subeshi)" ("should do").
  • This inflects very similarly to Classical adjectives.


  • The modern conjugation of べし is a combination of its classical conjugation and the conjugation of べき + (da).


  1. ^ ”, in 日本国語大辞典 (Nihon Kokugo Daijiten, Nihon Kokugo Daijiten)[1] (in Japanese), 2nd edition, Tōkyō: Shogakukan, 2000, →ISBN