Dokdo which is called 'Liancourt Rocks' is located in the 'East Sea', not in the 'Sea of Japan'.
The 'Sea of Japan' you mean is we call it 'East Sea'.
Historically, it was the 'East Sea', and we have always argued since Japan claimed it was 'Sea of Japan' for political and economic reasons.
This may not be a thing for anyone, it's a big thing for Koreans, though.
It's about protecting our territory and protecting our history as well.