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
「他山の石以て玉を攻むべし」という諺がある。
There is a proverb: 'One can use stones from another mountain to polish one's own gems.'
彼の失敗を他山の石以て玉を攻むべしの精神で受け止めよう。
Let's take his failure as a lesson for ourselves, in the spirit of the proverb.
The abbreviated modern form of the same proverb, used as a set phrase meaning 'a lesson learned from others' mistakes'. More common in contemporary Japanese.
From classical Chinese literature (Shijing). The literal meaning is 'stones from other mountains can be used to polish one's own gems', metaphorically meaning that others' faults or seemingly worthless things can be used for self-improvement.