'The Player of Games' (1988) by Iain M Banks

Jernau Morat Gurgeh, a famously skillful player of board games and other similar contests, lives on Chiark Orbital (space station), and is bored with his successful life. The Culture's Special Circumstances (SC) inquires about his willingness to participate in a long journey but won't explain further unless Gurgeh agrees to participate. While he is considering this offer, one of his drone friends, Mawhrin-Skel, which had been ejected from SC due to its unstable personality, convinces him to cheat in one of his games in an attempt to win in an unprecedentedly perfect fashion. The attempt fails, but Mawhrin-Skel uses its recording of the event to blackmail Gurgeh into accepting the offer with the condition that Mawhrin-Skel be admitted back into SC.

Gurgeh spends the next two years travelling to the Empire of Azad in the Small Magellanic Cloud, where a complex game (also named Azad) is used to determine social rank and political status. The game itself is sufficiently subtle and complex that a player's tactics reflect their own political and philosophical outlook. By the time he arrives, he has grasped the game but is unsure how he will measure up against opponents who have been studying it for their entire lives.