他山たざんの石以いしもって玉たまを攻おさむべし

expression

learn from others' mistakes; use others' faults to improve oneself

A classical proverb meaning that even seemingly worthless things or others' shortcomings can serve as a lesson for self-improvement. Often cited in its full form for literary or didactic effect; in everyday speech, the abbreviated 他山の石 is more common.

See also: 他山の石

• 「他た山ざんの石いし以もって玉たまを攻おさむべし」という諺ことわざがある。

  There is a proverb: 'One can use stones from another mountain to polish one's own gems.'

• 彼かれの失しっ敗ぱいを他た山ざんの石いし以もって玉たまを攻おさむべしの精せい神しんで受うけ止とめよう。

  Let's take his failure as a lesson for ourselves, in the spirit of the proverb.