磨ま穿せん鉄てっ硯けん

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.

• 彼かれの合ごう格かくは、まさに磨ま穿せん鉄てっ硯けんの努ど力りょくの賜たま物ものだ。

  His passing the exam is truly the fruit of unyielding diligence in his studies.

• 磨ま穿せん鉄てっ硯けんの精せい神しんで研けん究きゅうに打うち込こんだ。

  He devoted himself to research with the spirit of wearing a hole through his metal inkstone.