Meaning of "game of thrones"

I think part of the confusion is: if there is only one Iron Throne (as there is in the series), why is "thrones" plural in A Game of Thrones. The answer is that "A Game of Throne", "A Game of a Throne", and "A Game of the Throne" all sound really terrible to native English speakers.

Here you should interpret "thrones" as a generic noun, meaning thrones as an abstract concept rather than referring to any particular one. In English, if you have a countable noun, the generic must be expressed as plural (with no article). Possibly, the translation into Czech should have been a game in which one might win the (only) throne, if that phrase can be expressed reasonably succinctly in Czech.

In English the title is ambiguous as to whether the Game is among Thrones, by Thrones, about Thrones, or for Thrones. "Of" is a preposition with very little lexical meaning in English, and in this case it lends a bit of ambiguity. A direct translation to another language might lose that particular nuance.