Thanks for providing valuable informations.
I could get a lot of map informations to study from your site!
However, there is a miswritten letter.
In a map(https://www.mapsofworld.com/answers/geography/what-are-the-key-facts-of-japan/attachment/map-of-japan/), there is Sea of Japan(East Sea).
It seems like the water's real name is Sea of Japan..
But there is absolutely our Korea's water,,,!!
We've got a cost of evidences thet says the East sea is our water.
If you cannot believe this, you can visit http://dokdo.mofa.go.kr/eng/dokdo/reason.jsp.
In the site, there are a lot of evidences which can convince yourself that East Sea is Korea's territorial water.
So, I want you to correct the expression from "Sea of Japan(East Sea)" to just "East Sea."