What is the written kanji on the paper fan in season 2 episode 2?


In the anime _Kaguya-sama wa Kokurasetai_ , Season 2, Episode 2, when Kaguya
gives a paper fan for Shirogane's birthday, it shows that she wrote a kanji
that, according to the subtitles, is " _unyielding diligence in one's studies_
".

[![](https://i.stack.imgur.com/nYgXE.jpg)](https://i.stack.imgur.com/nYgXE.jpg)

[![](https://i.stack.imgur.com/nfuoe.jpg)](https://i.stack.imgur.com/nfuoe.jpg)

[![](https://i.stack.imgur.com/Pyn9M.jpg)](https://i.stack.imgur.com/Pyn9M.jpg)

I'd like to ask if the meaning is correct. I tried to write it, but as it's in
Japanese calligraphy, I couldn't make it.




**The kanji on the paper fan is 磨穿鉄硯【ませんてっけん】.**

According to
[weblio](https://ejje.weblio.jp/content/%E7%A3%A8%E7%A9%BF%E9%89%84%E7%A1%AF),
the translation is correct:

> showing unyielding diligence in one's studies; wearing a hole through one's
> metal inkstone from constant studying

This is actually a [_yojijukugo_](https://en.wikipedia.org/wiki/Yojijukugo) or
"four-character idiom" that is easier to search compared to identifying the
characters in Japanese calligraphy directly.




**The kanji on the paper fan is 磨穿鉄硯【ませんてっけん】.**

According to
[weblio](https://ejje.weblio.jp/content/%E7%A3%A8%E7%A9%BF%E9%89%84%E7%A1%AF),
the translation is correct:

> showing unyielding diligence in one's studies; wearing a hole through one's
> metal inkstone from constant studying

This is actually a [_yojijukugo_](https://en.wikipedia.org/wiki/Yojijukugo) or
"four-character idiom" that is easier to search compared to identifying the
characters in Japanese calligraphy directly.

