〜べし
beshi
By Nihongo PathUpdated
Meaning
should; must; ought to (classical, sentence-final); is worth …ing
Vる + べし is the classical ancestor of べきだ, used at the end of a sentence as a crisp command or recommendation: 大志を抱くべし = "Be ambitious"; 必ず観るべし = "You must watch it". It survives in slogans, proverbs, headlines, and playful emphatic writing. する becomes すべし.
Written Japanese: slogans, mottos, proverbs, headlines, reviews (一見の価値あり、必ず観るべし), and humorous emphatic style. Not used in ordinary conversation, where べきだ / なければならない / たほうがいい are normal. Related forms: べからず (prohibition), べく (in order to), べき (attributive).
Formation
V = verb, N = noun, A = adjective.
Vる + べし (抱くべし・観るべし)する → すべし (努力すべし)Sentence-final only (attributive is べき: 読むべき本)Family: べし (should) / べからず (must not) / べく (in order to) / べき + N
Visual diagram
べし
classical auxiliary of obligation
- + べし観るべしsentence-final: you must watch it
- + べき観るべき映画attributive: a film one should see
- + べく観るべく劇場へpurpose: in order to watch
- + べからず観るべからずprohibition: must not watch
Natural examples
若者よ、大志を抱くべし。
わかものよ、たいしをいだくべし。
Young people, be ambitious.
A famous motto (Clark's 少年よ、大志を抱け rendered with べし).
この映画は一見の価値あり、必ず観るべし。
このえいがはいっけんのかちあり、かならずみるべし。
This film is worth seeing; you must watch it.
Review style: 一見の価値あり、必ず観るべし.
後生畏るべし。
こうせいおそるべし。
The young are to be respected (proverb: those who come after may surpass us).
A proverb from the Analects; べし gives it weight.
学生たるもの、まず基礎を固めるべし。
がくせいたるもの、まずきそをかためるべし。
A student should, first of all, build a solid foundation.
たるもの + べし: motto style.
この店のカレー、辛党なら一度は試すべし。
このみせのカレー、からとうならいちどはためすべし。
If you like spicy food, you must try this restaurant's curry at least once.
Playful review register.
Similar grammar and the difference
The modern form. べきだ is used in speech and writing; べし is sentence-final, classical, and slogan-like. Compare side by side
The negative of べし: "must not", on signs and in fixed phrases. Compare side by side
The purpose form: "in order to". Same root, different function. Compare side by side
Common mistakes
- ✗
- 読むべし本
- ✓
- 読むべき本
- Why
- Before a noun the form is べき; べし is only sentence-final.
- ✗
- 勉強しべし
- ✓
- 勉強すべし
- Why
- する becomes すべし.
- ✗
- （会話で）明日は早く来るべし。
- ✓
- 明日は早く来るべきだ。/ 早く来てね。
- Why
- べし in conversation sounds like a slogan or a joke; use べきだ or a normal request.
Learn the family together: べし / べき / べく / べからず / べくして. Headlines and ads use べし for punch: 今すぐ申し込むべし. In fiction it characterizes old-fashioned or authoritative speakers.
JLPT N1 tips
On the exam
- In 文法形式の判断, a slogan-like or headline-like sentence ending in a command is べし; before a noun the answer is べき instead.
- Check する: すべし is correct, しべし is not.
- In 並べ替え, べし is always the final chunk.
Frequently asked questions
What does 〜べし mean?
should; must; ought to (classical, sentence-final); is worth …ing. Vる + べし is the classical ancestor of べきだ, used at the end of a sentence as a crisp command or recommendation: 大志を抱くべし = "Be ambitious"; 必ず観るべし = "You must watch it". It survives in slogans, proverbs, headlines, and playful emphatic writing. する becomes すべし.
How do you form 〜べし?
Vる + べし (抱くべし・観るべし) / する → すべし (努力すべし) / Sentence-final only (attributive is べき: 読むべき本) / Family: べし (should) / べからず (must not) / べく (in order to) / べき + N. V = verb, N = noun, A = adjective.
When is 〜べし used?
Written Japanese: slogans, mottos, proverbs, headlines, reviews (一見の価値あり、必ず観るべし), and humorous emphatic style. Not used in ordinary conversation, where べきだ / なければならない / たほうがいい are normal. Related forms: べからず (prohibition), べく (in order to), べき (attributive).
What is the difference between 〜べし and 〜べき / 〜べきだ?
The modern form. べきだ is used in speech and writing; べし is sentence-final, classical, and slogan-like.
What is the difference between 〜べし and 〜べからず / 〜べからざる?
The negative of べし: "must not", on signs and in fixed phrases.
What is a common mistake with 〜べし?
Wrong: 読むべし本 Right: 読むべき本 Before a noun the form is べき; べし is only sentence-final.
Quick check
迷ったときは、初心に（ ）べし。