noun
unyielding diligence in one's studies; wearing a hole through one's metal inkstone from constant studying
A yojijukugo (four-character idiom) used to praise or describe extreme perseverance in academic pursuits. The literal image is of grinding through a metal inkstone by constant use.
彼の合格は、まさに磨穿鉄硯の努力の賜物だ。
His passing the exam is truly the fruit of unyielding diligence in his studies.
磨穿鉄硯の精神で研究に打ち込んだ。
He devoted himself to research with the spirit of wearing a hole through his metal inkstone.
A yojijukugo derived from a classical Chinese story about a scholar who studied so diligently that he wore a hole through his metal inkstone. The exact historical origin is uncertain, but the phrase is conventionally associated with extreme academic perseverance.