To be fair, it's not like IRL names of some countries are that original either; the German name for Austria (Österreich) translates to "Eastern Realm".
A Japanese embassy led by Hasekura Tsunenaga had visited several European nations between 1614-1616, some members of his embassy decided to stay in Europe and there are several hundred people living Spanish village of Coria del Rio with surname Japón, who are descendants of those Japanese who...
Fucking lol, learn some history incel, sex before marriage was common and accepted in Japan before, during and after this period: https://en.wikipedia.org/wiki/Yobai