〜べし / 〜べからず (classical should / must not)
〜べし / 〜べからず Formality Level: Archaic / Literary — laws, school rules, mottos, formal declarations, literary prose Classical Origin: べし is one of the most important auxiliary verbs in classical Japanese ( 文語 ). It appears throughout the Manyoshu , the Kokinwakashu , Heian-period prose, medieval warrior codes, and Edo-period legal documents. べし derives from the adjective べき ( beki ) which itself comes from Old Japanese be-si expressing appropriateness,...