What are the laws concerning copyright of chess games? Here is my specific situation: I have written a novel in which two characters play a game, the moves of which follow exactly a known game between two ranked players in ChessGames.com. Must I get permission from the two real players? Or must I only credit them in the acknowledgments of the novel? Or need I even do that? Any information, especially with legal citations, would be greatly appreciated!
Chess games without annotation can't be possibly copyrighted. You don't need to inform them. You don't need to acknowledge them.

I've been using Carlsen's games (without annotation) for commercial. I literally sell his moves and the games. So far, the world champion has not complained.

Game annotations are protected by the laws. Make sure you only use the game moves.

@itub has some links, such as:

https://chess24.com/en/read/news/us-judge-agrees-with-chess24-on-chess-moves