他た山ざんの石いし

noun

lesson from others' mistakes; food for thought

Idiomatic expression meaning that one can learn from the mistakes or failures of others, just as stones from other mountains can be used to polish gems. Often used in the phrase 他山の石とする.

See also: 他山の石以て玉を攻むべし

• 彼かれの失しっ敗ぱいを他た山ざんの石いしとして、同おなじミスを繰くり返かえさないようにしよう。

  Let's learn from his mistake and make sure we don't repeat it.

• あの会かい社しゃの倒とう産さんは、我われ々われにとって他た山ざんの石いしだ。

  That company's bankruptcy is a lesson for us.