a proverb meaning one should learn from others' mistakes or experiences to refine oneself; literally, 'use stones from other mountains to polish a gem.'
彼は『他山の石以て玉を攻むべし』と言って、競合他社の失敗から対策を学んだ。
He said 'use others' mistakes to polish yourself' and learned countermeasures from a rival company's failures.
古いことわざ『他山の石以て玉を攻むべし』は、自己改善の重要性を説いている。
The old proverb 'use stones from other mountains to polish a gem' advocates the importance of self-improvement.