I recall reading a story that the Guatemalan Defense (1. ... b6, 2. ... Ba6) is named after a game of correspondence chess that was played between (presumably some chess team representing) Guatemala and another country. I've been unable to find this back despite quite some googling, however. Does anyone have a reference or clarification?
The reason it is called is because it is used by a Guatemala Chess Club.
According to wikipedia "so-named because the Guatemala Chess Club used the line in a 1949 correspondence game."
So the reason is because it is played by a chess club based in Guatemala in a 1949 correspondence game.