# べくもない: cannot possibly be > Learn べくもない (beku mo nai), an N1 grammar meaning 'cannot possibly be; there's no way that…', with formation, nuance, examples, and comparison to はずがない. JLPT level: N1 · Updated: 2026-05-18 · Canonical: https://hane-app.com/blog/n1-beku-mo-nai/ **べくもない** means **cannot possibly be; there's no way that…**. It is a **JLPT N1** Japanese grammar pattern used to negate an action or state based on what should be possible or expected — highlighting that something is utterly impossible given the circumstances. This grammar point often appears in formal writing, literary commentary, news analysis, and JLPT N1 reading passages. If you want to express that something simply **cannot** happen, even though it might be expected, **べくもない** is a precise and emphatic tool. ## What does べくもない mean? Use **べくもない** when you want to say that a certain result or action is entirely unattainable — not because of a specific prohibition, but because reality makes it impossible. The pattern carries a sense of *should be possible, yet isn’t*. Natural translations include: - cannot possibly be ; there is no way that … ; it is not possible to … The right English choice depends on the verb in question (know, compare, reach, etc.) and the tone of the sentence. ## How to form べくもない
V (dictionary form) + べくもない
- 知る(しる)（しる）→ 知るべ(しるべ)くもない - 比べる(くらべる)（くらべる）→ 比べる(くらべる)べくもない - 及ぶ(およぶ)（およぶ）→ 及ぶ(およぶ)べくもない This pattern is frozen: you never add だ or adjust ない. The べく part is the adverbial form of the classical auxiliary べし, and the whole phrase is treated as a predicate adjective phrase. It’s almost always used as a sentence-ending predicate or to modify a noun (e.g., 知る(しる)べくもない事実(じじつ)). In JLPT questions, the wrong answer choices often give you べきもない or べからざる, so remember that only the く-form (べく) attaches to もない. ## When is べくもない used? Use **べくもない** in situations like: - commenting that something cannot possibly be known, compared, achieved, etc. - pointing out an obvious contradiction between expectation and reality - delivering a sober, often resigned judgment in formal writing Tone and register: - **formal, written, or solemn** — rare in casual speech - carries a weight of finality; the speaker has already concluded there is no way You’ll see it in newspaper editorials, critical essays, and some historical fiction. ## べくもない example sentences
彼(かれ)の真意(しんい)など、知しるべくもない。
There's no way to know what his real intentions were.
written opinion
この風景ふうけいは写真しゃしんに収おさめるべくもない。
This scenery cannot possibly be captured in a photograph.
descriptive emotional
その苦くるしみは、言葉ことばに尽つくすべくもない。
No words could ever fully capture that suffering.
formal literary
これほどの傑作けっさくは、他ほかの作品さくひんと比くらぶべくもない。
A masterpiece like this simply cannot be compared to other works.
review argument
わずか一週間いっしゅうかんで完成かんせいなど、望のぞむべくもない。
There's no way anyone could hope to finish it in just one week.
realistic negation
その真相しんそうは、歴史れきしの闇やみに消きえ、今いまとなっては知しるべくもない。
The truth has vanished into the shadows of history — at this point, it cannot possibly be known.
historical solemn
After reading each sentence, notice the gap between what *should* be knowable and what *is* actually knowable. That’s the essence of べくもない. ## Nuance of べくもない The core nuance is **impossibility rooted in the nature of the verb itself**. It’s not just “can’t” — it’s “no matter what, it’s not in the cards”.
💡
Key feeling: 知るべ(しるべ)くもない doesn’t just mean “I don’t know”; it means “there’s no path to that knowledge”. The pattern frames the impossibility as an inherent, unchangeable fact — almost like a law of physics applied to the situation.
This differs from saying 知る(しる)ことができない (I am unable to know) or 知る(しる)はずがない (it cannot be that I know). べくもない emphasizes that even the *precondition for possibility* is absent — the very act of knowing is out of reach, not just blocked by effort or chance. ## べくもない vs はずがない Both **べくもない** and **はずがない** express strong negation of a possibility, but their focus differs. **べくもない**: - impossibility rooted in the expected, “should be” nature of the verb - often tied to verbs like know, compare, reach, describe - tone: formal, weighty, final **はずがない**: - general “cannot be the case” based on logical reasoning - applies to any situation, person, or event - tone: argumentative, everyday
べくもない
知るべ(しるべ)くもない
When you want to say the act of knowing is categorically impossible.
歴史(れきし)の真実(しんじつ)は今(いま)となっては知る(しる)べくもない。
The historical truth can no longer be possibly known.
vs
はずがない
知る(しる)はずがない
When you reason logically that someone cannot know, e.g., because they weren’t there.
彼(かれ)が知る(しる)はずがない。だってまだ誰(だれ)も話し(はなし)ていない。
He can’t possibly know. No one has told him yet.
Choose べくもない when you want to close the door on possibility with a tone of finality. Stick with はずがない when you’re simply pointing out a logical contradiction. ## Common mistakes with べくもない
❌
知れ(しれ)べくもない
✅
知るべ(しるべ)くもない
Attach べくもない to the dictionary form, not the potential or passive form.
❌
彼(かれ)は行く(いく)べくもない。
✅
彼(かれ)が行く(いく)はずがない。
べくもない is rarely used with simple movement verbs like 行く(いく). Reserve it for verbs of cognition, comparison, measurement, and description.
❌
べくもないことをするべきではない。
✅
不可能(ふかのう)なことをするべきではない。
Don’t use べくもない as a generic substitute for “impossible”. It needs a verb that carries the expectation of being done.
A good rule: if you can replace “cannot possibly” with “there’s no way to [verb]”, and the verb is something like know, compare, reach, or describe, べくもない is likely a good fit. ## Is べくもない on the JLPT?
N1

Reading: you should recognize it in formal passages and know it means impossibility.

Grammar: might appear in the sentence-structure section, often together with other classical auxiliaries like べく or べからず.

Usage: not typically required in production, but knowing the pattern helps you parse complex N1 texts.

Even if you don’t need to write it, understanding べくもない saves time when you encounter it in the Reading section. Look for the “dictionary form + べくもない” cluster and mentally replace it with “cannot possibly be ~”. ## Practice questions for べくもない
1
Use 知るべ(しるべ)くもない in a sentence about a secret that can never be uncovered.
2
Write about a talent that is so far beyond ordinary people that it 比べる(くらべる)べくもない.
3
Describe a natural disaster’s damage, saying that words cannot fully capture it (use 尽くす(つくす)べくもない).
4
Explain why an incomplete manuscript cannot possibly live up to the author’s original vision (及ぶ(およぶ)べくもない).
Keep your sentences formal and written-style. Adding a context like a historical article or critical review will make the pattern feel natural. ## Learning path for べくもない
1
Memorize the formation: V‑dict + べくもない. Say it aloud with 知る(しる), 比べる(くらべる), 及ぶ(およぶ), and 尽くす(つくす).
2
Read a short editorial or essay summary in Japanese. Every time you see べくもない, pause and check whether “cannot possibly be” fits the context.
3
Write three sentences with べくもない. Then rewrite those same sentences using はずがない and notice the tone shift — do they feel more logical or more resigned?
4
Expand to related classical patterns (see below) so you can recognize the べく family when it appears across JLPT N1 materials.
## Related grammar to review next - [べく](/blog/n1-beku/) — positive adverbial form “in order to; should” - [べくして](/blog/n1-beku-shite/) — “as expected; destined to” - [びる・びて・びた](/blog/n1-biru-bite-bita/) — classical suffix giving a “seems like” nuance - [べからず・べからざる](/blog/n1-bekarazu-bekarazaru/) — strong prohibition “must not; cannot be allowed” ## Learn べくもない with Hane If you want to review **べくもない** together with the related classical patterns above, Hane helps you practice Japanese in short, focused sessions. Browse more lessons here: - [All grammar lessons](/blog/) - [JLPT N1 grammar lessons](/blog/n1/)