自じ分ぶんの首くびを絞しめる

expression, ichidan verb

cut one's own throat; dig one's own grave; bring ruin on oneself

Idiomatic expression meaning to do something that ends up harming oneself, often through one's own words or actions.

• あんな発はつ言げんをしたら、自じ分ぶんの首くびを絞しめることになるよ。

  If you make a remark like that, you'll be digging your own grave.

• 値ね下さげ競きょう争そうは結けっ局きょく、自じ分ぶんの首くびを絞しめるだけだ。

  A price war will only end up cutting your own throat.