I want to create a Chess game that has different rules. Can I do this?

Question

:This question is just for argument purposes to make a point:

Chess is an ancient game. No one knows who invented it. So probably no patent, or inventor’s rights. Can I make another chess game with different rules, and sell it? Can I do this? Will this be legal?

Answer 1

Sure, no problem. It would be best to call it something other than chess though, to avoid confusion. As you are no doubt aware, tournament level chess has very specific rules that are set by FIDE, the World Chess Federation (web site linked below):

http://www.fide.com/index.php

The broader point, though, is that things like that which have been around for many years and have no copyright or patent are considered to be in the public domain and therefore can be used without permission.