The exception to the rule
If you change any rule it is going to affect the game
Here is an example, it is a well known game between Fischer and Petrosian
It is often called The Four Queens Game
After black plays Bg4 in the early opening stockfish gives the best move for white as d4
White however plays h3 and a few moves later black plays d4
With my rule the black pawn on d4 is a blocking pawn.
It stops the pawn jump c2-c4, it does not however stop the pawn step c2-c3.
Later white plays a3 and b4 to open up lines on the Queen side, b4 however creates a weakness on c3 which black exploits with his Knight
White finally does play c2-c4, this would not be possible with my rule
If I was playing the game using my rule after Bg4 by black I would play d4 and never allow black to play d4
I would not, using my rule, play b2-b4 creating a huge hole on c3 and saddling me with a backward pawn on c2
My rule does affect the pawn structure, as does the en passant rule in chess
But the rules are not the same, and the effect of both rules is subtle and different
Why did you write a novel on intellectual property law? I don't understand what this has to do with chess. Chess is over 1,000 years old. It's not patented and can never be patented. It can't even be covered under basic copyright law. You could make "Tazmanian Devil Chess" and have it be no different than chess, sell it, and no one would be able to sue you or claim you're infringing on any rights (other than Warner Bros. for infringing on their rights to the Tasmanian Devil character). On top of that, any chess variant is just a rip-off of chess. Why should you be able to own the rights to it? If you take the Facebook logo and just change the color, you would get so sued. You're not creating anything.
I am making a new game girl
Start reading from post # 1 if you want to understand