IANAL, it seems, game mechanics can't be copyrighted, unless you use the same images for cards / board, or literally copy the rule book.
> In short: you can trademark the name, logos. Have copyright on art (even the board itself as art). You can't copyright the mechanics, processes or rules. That explains the Monopoly/Scrabble clones.
https://www.reddit.com/r/gamedev/comments/10f2nov/comment/j4...
which refers to this youtube video: