Leaving aside the issue of whose world view is correct, there seem to be two Japanese readings for the Korean word for the body of water between the two countries:
NHK writes 東海 【とんへ】 but wwwjdic writes 東海 【とうかい】
アメリカ軍【ぐん】「日本海【にほんかい】を『東海【とんへ】』と書 【か】いたのは間違 【まちが】い」
U.S. military: "Writing 'East Sea' for Sea of Japan was a mistake"
Why are there two Japanese readings for the Korean word? Are they interchangeable and equally acceptable as readings of the Korean name?