わけにはいかない
- 1Cannot do something because circumstances, common sense, or social obligations do not allow it.Ex. 1
- 2With a negative verb, must do something because not doing it would be unacceptable under the circumstances.Ex. 2
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It is used in both speech and writing to explain why an action is ruled out by one's situation, a promise, or a sense of responsibility. It often follows a stated reason such as 〜から or 〜以上. Unlike plain できない, it never describes a lack of ability. It stresses that the circumstances make the action unacceptable.
Do not use わけにはいかない for physical or skill-based inability; use the potential form or できない instead.
Note that the ない-form version expresses obligation, meaning 'must do,' not 'cannot do.'
Learners sometimes confuse it with わけではない ('it is not that…') or わけがない ('there is no way…'), which have different meanings.
- 〜ないわけにはいかないN1「〜ないわけにはいかない」is this pattern attached to the ない form; it means specifically 'cannot not do / must do' and does not carry the dictionary form's 'cannot do' meaning. For emphasis, you can say 「ないわけにもいかない」.
- ざるを得ないN2「ざるを得ない」corresponds only to 「ないわけにはいかない」; it stresses being forced by circumstances with no alternative and leans formal/written. It often pairs with 「言う」「認める」to mean 'can't help but say' or 'can't help but admit'.
- 〜ほかないN3「ほかない」attaches to the dictionary form and means having no choice but to do something, in a formal/written register. It is close only to 「ないわけにはいかない」: the latter stresses that propriety and responsibility make it impossible not to act, while 「ほかない」stresses having no path left and reluctantly accepting.
- しかないN3「しかない」means circumstances leave you no choice but to do something; it resembles 「ないわけにはいかない」but does not stress propriety or responsibility. It can also attach to nouns to mean 'only...', and it cannot be used to express 'cannot do'.
- なければいけない / なければならないN4「なければいけない/ならない」means only 'must' and corresponds only to 「ないわけにはいかない」. It states necessity or obligation directly, can also attach to adjectives and nouns, and does not highlight the speaker's own judgment after weighing what is proper.
- ことはないN3「ことはない」means 'no need to do' and is often used to reassure the listener. 「わけにはいかない」is 'cannot do' out of propriety or circumstances, and 「ないわけにはいかない」is 'must do' — the exact opposite of 'no need' — so they cannot be interchanged.
〜ないわけにはいかない is the negative-verb use of this pattern, meaning 'must, given the situation.' ざるを得ない is more formal and stresses reluctant compulsion, 〜ほかない and しかない mean there is no other option, なければならない states general obligation or rules, and ことはない means there is no need to do something.
