べし

Japanese

Etymology

Alternative spelling
可し (obsolete)

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

Pronunciation

IPA^(key): [be̞ɕi]

Suffix

べし • (-beshi)

(attaching to terminal form) must, shall
Antonym: まじ (maji)
1. indicating certainty
  地(ち)方(ほう)路(ろ)線(せん)のいくつかはやがて廃(はい)止(し)されるべき運(うん)命(めい)にある。
  Chihō rosen no ikutsuka wa yagate haishisarerubeki unmei ni aru.
  Some of the local railways will soon be abolished.
2. indicating requirement
  この件(けん)については君(きみ)が責(せき)任(にん)をとるべきだ。
  Kono ken ni tsuite wa kimi ga sekinin o torubeki da.
  You should take responsibility on this.
  
  明日(あした)は八(はち)時(じ)までに出(しゅっ)勤(きん)すべし。
  Ashita wa hachiji made ni shukkin-subeshi.
  You should work until eight o'clock tomorrow.
  
  英(えい)語(ご)は声(こえ)を出(だ)して読(よ)むべきだ。
  Eigo wa koe o dashite yomu beki da.
  You should read English aloud.
  
  来(らい)年(ねん)の博(はく)覧(らん)会(かい)開(かい)催(さい)に間(ま)に合(あ)わせるべく、突(とっ)貫(かん)工(こう)事(じ)が行(おこな)われている。
  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 notes

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.
This inflects very similarly to Classical adjectives.
The verb する (suru, “to do”) typically takes the classical terminal form す (su), rather than the modern terminal form する (suru), when used with べし (beshi): すべし (subeshi) ("should do").
- However, there is a minority that uses するべし (surubeshi).^[2]
It is common to see the adnominal form べき (beki) + auxiliary だ (da) in terminal position instead of the expected terminal form べし (beshi).

Inflection

Inflection of べし
Stem forms
Imperfective (未然形)	べから	bekara
Continuative (連用形)	べく	beku
Terminal (終止形)	べし	beshi
Attributive (連体形)	べきべかる	beki bekaru
Hypothetical (仮定形)	べけれ	bekere
Imperative (命令形)	—	—
Key constructions
Informal negative	べきじゃない	beki ja nai
Informal past	べきだった	beki datta
Informal negative past	べきじゃなかった	beki ja nakatta
Formal	べきです	beki desu
Formal negative	べきではありません	beki de wa arimasen
Formal past	べきでした	beki deshita
Formal negative past	べきではありませんでした	beki de wa arimasen deshita
Conjunctive	べくべくて	beku bekute
Conditional	べきだったら	beki dattara
Provisional	べければ	bekereba
Volitional	べきだろうべきでしょう	beki darō beki deshō
Adverbial	べく	beku
Degree	—	—

Classical conjugation of "べし" (ク活用, see Appendix:Japanese verbs.)
Stem forms
Irrealis (未然形)	べく^[1] べから^[2]		beku bekara
Continuative (連用形)	べく^[1] べかり^[2]		beku bekari
Terminal (終止形)	べし		besi
Attributive (連体形)	べきべかる		beki bekaru
Realis (已然形)	べけれ		bekere
Imperative (命令形)	べかれ		bekare
Key constructions
Negative	べからず		bekarazu
Contrasting conjunction	べけれど		bekeredo
Causal conjunction	べければ		bekereba
Conditional conjunction	べくば		bekuba
Past tense (firsthand knowledge)	べかりき		bekariki
Past tense (secondhand knowledge)	べかりけり		bekarikeri
Adverbial	べく		beku

^[1]Without auxiliary verb.
^[2]With auxiliary verb.

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

References

^ “可”, in 日本国語大辞典 [Nihon Kokugo Daijiten]‎^[1] (in Japanese), concise edition, Tokyo: Shogakukan, 2006
^ https://www.nhk.or.jp/bunken/research/kotoba/20210401_3.html