having no effect; waste of effort
Idiomatic expression literally meaning 'a clamp on tofu', used to describe a futile or pointless action that produces no result.
Warning him is like trying to clamp tofu — it's completely useless.
No matter how much I tried to persuade him, it was a waste of effort; he wouldn't listen.
Means 'pushing against a shop curtain', implying no resistance or effect; 豆腐に鎹 focuses more on the impossibility of getting a grip or making an impact.
Standard kanji spelling for this idiomatic expression.
Mixed kanji-kana spelling; may be easier for learners to read.
Literally “a clamp in tofu”: a metal 鎹 driven into soft tofu cannot take hold. The image expresses advice or effort that has no effect.